The thing to understand here is that those "retro games" are decades old, gaming advanced since then. Those games were simple because the technology of the time couldn't really do much better.
It's also important to note the absolutly punishing difficulty of a lot of those simple games, that is not present in the Iphone games, and that is something important that is missing from this equasion. Games on the Iphone are designed so just about anyone can sit down and beat them with minimal effort and a bit of repetition, compared to many of those retro games where that was hardly the case.
The thing to understand also is that the divide exists not so much because of sneering arrogance on the part of actual hardcore gamers, but because the industry has grown so greedy and corperate that it is not producing much in the way of hardcore games. Nobody would give a crap if all the developers were not so focused on making accessible, casual, games for the lowest human denominator. If we were seeing an equal number of deep, hardcore titles coming out this divide wouldn't exist. The gaming industry figures it can produce those casual games more easily and cheaply, and hit a much larger audience, and this make more money. Hardcore games ARE profitable, but not as profitable as casual shovelware, so shovelware is primarily what we see.
To argue that the iphone or your typical tablet is as valid a gaming platform as a console that was out decades ago, is to defend a gaming not only ceasing to move forward, but literally regressing back to it's infancy in a practical sense.
When it comes to people crying over missing the old school, it should be noted what those people are saying they want are things like "Demon's Souls" or "Dark Souls" modern technology, decent depth, and a reasonably steep learning curve combined with punishing difficulty that makes progress inherantly rewarding. You however see ridiculously few games of that sort, just as you increasingly see very few deep and complicated RPGs.. which traditionally don't have the punishing difficulty, are are (for good reason) complex enough to not be approachable to the casual market. Today all RPGs need to generally be simplified or spliced into some kind of action game that undercutes the entire point of having an RPG to begin with.
Truthfully with so many gaming-media personalities coming out in defense of casual games and gamers, I confess to some growing concern. What should be the guardians of the industrial seem to be falling into line with the mass-market demands, the same way professional reviewers did before them.
Or in short, there is nothing inherantly wrong with casual games, as long as there are enough serious games produced to meet the demand, and really there aren't since the casual market has ultimatly been replacing them. Defending a game as being good as something from the 80s or early 90s is really kind of sad given that we're almost into 2012.