I think the bottom line is greed. It's not just about running a successful game that is making money, but a matter of the degree of success. People look at the industry leaders and figure "if we can't match that, we're failing". It's increasingly like that with all generes.
The microtransaction model is increasingly popular because it has more potential to make money, since if it's implemented correctly the company can make more than the $15 a month people pay for subscriptions. No matter how they dress it up with analogies to school and college, the bottom line is that it turns into a "pay to win" situation as anyone willing to pay for the advantages to begin with is liable to be willing to put in the effort. With two players putting in equal effort, the one who winds up spending the most money is going to wind up ahead.
I don't think it's an "evolve or die" thing as much as it is greed. A lot of people supporting the model want all games to go to a similar model, due to the large numbers of gamers who will only play subscription based games in the core market in the US. You see a LOT of comments about this in various games out there, and I think the guys running microtransaction based games tend to overlook all the people who DON'T go to their game due to the microtransactions, or just figure "I'll stick with WoW, thanks".
It's also an important thing to note that the games that became successful in the US off the microtransaction model, are also games that had a substantial built in fan base to begin with. It's impossible to overlook that "Lord Of The Rings", "Dungeons and Dragons", "Warhammer" and even "Champions" were storied properties before the MMOs. Lord Of The Rings is a REALLY popular world setting, and Dungeons and Dragons and Warhammer have defined entire generes of non-computer gaming and carried the publication of entire novel series. "Champions" seems to be the loser of the group (though still going) though again, that's another property that has a huge built in fan base... how many books for the Champions RPG were published? Think about it. All of those games have people that are going to keep paying whatever it takes BECAUSE of what the games are about. The guy who constantly re-read things like "Guardians Of The Flame" and the "Gameearth" series and wished they could live in a D&D game can live out that fantasy to some extent with DDO for example. This kind of established/captive/addicted audience can't be discredited, as it's ripe for exploitation, which is something a lot of companies have figured out in other arenas in the past.
When it comes to the Asian games, understand also that the whole situation down there is a lot differant, a lot has been written about it. The pricing is differant, and the goverment is heavily involved in controlling who can do what with games. What's more ownership of personal computers is something that has been increasing, but the business model being looked at was based around people paying for access to games in Bangs (Asian Internet gaming cafes). See, a guy in Asia who doesn't own a computer, and can't login every day, is going to find paying a membership fee kind of pointless... he CAN however maintain a game account and login to it whenever he goes to a Cafe running the game and using his password, and perks attached to his character are something he can ultimatly keep, and a way for these games to make money. I think a lot of people looking at the microtransaction system tend to overlook how this kind of thing evolved, and also the changing face of Asian gaming (which there have been articles about) and how it's going to have to evolve with the population... and of course how things like the way the internet and international business is limited and so on influance communication technologies there.
There are plenty of free to play games making a bunch of money, however I think a lot of companies that can keep a bit of a reign on their short term greed realize that this kind of system is simply a fad, and what's more the very thing that makes it profitable... some idiot paying real money for a virtual item, is not something a lot of people are going to do. What's more it represents a barrier to bringing in new people and expanding the market because someone who has never gamed online is going to rightfully say "I am not going to play a game that requires me to pay constantly to succeed", and MMOs will go from a slow growth to no growth.
Understand also that like it or not there is a certain degree of intelligence and dedication involved in playing ANY real MMORPG type game. Far more than a browser based game like say "Farmville". The people exploited by that kind of model, are pretty much stuck in that cosm of gaming, getting those people to say transition from "I'm going to click on my sheep" to say leveling up characters, engaging in competitive PVP, and optimizing gear, while performing combat operations on the level of military drills (raids), pretty much isn't going to happen. Sure, MMOs *are* being dumbed down, but at the same time there is a certain "floor" they really can't go below while retaining their distinct identity from things like browser based Facebook games.
These are my thoughts, it's about greed as opposed to evolution, and truthfully I don't think it's a sustainable trend. I think Asia is slow to change, but as you see more and more personal computers (which are already affecting the bangs) and changes to the mentality of people there involving gaming, the microtransaction system is going to die... albiet it's going to be slow, and nasty, because it's so heavily entrenched. Trying to root that system in markets like the US might appeal to some very greedy people, and succeed to some extent, but I don't think it has quite the same chance of becoming what some people want it to be due to the differances in the market and what it's going to do to the long term growth of the industry.
As a final note for those that read this far, I will say that I think one of the problems with MMO development right now is that the genere became popular with publishers because they figured that for the same general amount of effort as making a decent hundred hour single player RPG, they could use those maps and game engines... and a similar amount of effort for a persistant world, and make the box sales plus membership fees and then be able to go swimming in giant bins full of money. For a while this was true... but then certain companies started raising the bar and taking an attitude about designing MMOs for MMOs, optimizing them for that enviroment to a huge degree, and putting in enough content to sustain them. As this happened the quality rose, and with it the cost to develop at that area. It got to the point where someone couldn't poop out a game for a few million and charge a membership fee. It went from a few million to tens of millions to even consider it, and as the established games get bigger the price is getting into the hundreds of millions.... with that development fee of course comes an increasingly long term view being required, with publishers needing to wait years potentially to see returns... long term investments being less popular than what was seen as a short term, high return investment. The free to play model *IS* a potential refuge for those short term return games, that are now B and C grade even if just 6 years ago they might have been considered something impressive.
All told, I'm perfectly cool with fewer, higher quality, subscription based games.
... also as I pointed out above, the decent microtransaction games in the US are generally speaking those with big liscences which came with substantial fan bases attached to those liscences before the games were even conceived of. I'm sure there is an exception somewhere, but that is the general rule, and it's not something that can be overlooked.
Thanks to those who read this far.