I know this comes many weeks after this video, and I don't know if anyone else as said this in the over 200 comments posted here, but I feel like know the reason (or one of them) why Square-Enix made the sudden choice it made that these games weren't worth making any more, and it's about the same thing can be said about why Konami and Capcom had neutered their highly popular Survival Horror series.
Sometime in the later half of the PS2 era of gaming the internet (and I'm sure you can see where this is going, with the inclusion of that word) began to come into it's own as we know it today. With that came the fledgling days of the war over what's the best thing ever, for everything ever. During that time the PS2 especially was seeing a wide array of varied titles seeing huge amounts of love, most of which are still beloved, but, as evidenced in Jim's video, shoved to the side genre, such as survival horror and proper RPGs.
Somewhere along the way during all this there was a large anonymous rumbling in the distance (at least in the western end of the internet) comprised of thousands of little voices thundering in unison saying that JRPGs were boring, slogging, shite, and that people didn't want to spend 50+ hours on* these games any more.. A similar voice was also over the dark horizon that said survival horror games weren't favored because -ironically- "they're scary."
Now, I think this caused the companies that saw huge success from these genres to panic. This sort of outpouring of criticism from the very people who line their coffers with the treasure of hundreds of countries was something they didn't feel they should ignore in such a time of newness for things like that to be said so openly and without couth. Now we know they're fine just ignoring us and going about their business, largely forgoing everything we say to pad their botton line, under the black flag of "they'll buy anything, even when they complain about it) --but they had to learn that they could do that, before they could do that.
Survival horror may have actually had hard numbers to the effect that helped them to dwindle from the big-publisher spotlight; because it seems like we were always told that these games didn't have huge because horror as a genre in any visual medium is something of a hard sell. But a company like Square-Enix, who's entire industry presence, between both companies that Voltroned up in 2003 to comprise the whole entity we know today, had been the long, turn based, story heavy, JRPG, suddenly started to bail out on what had been long established as it's lifeblood somewhat shortly after these sorts of comments started becoming common place to see across the internet.
Funny enough, in the time these comments started to show the most, was the time between FFX and FFXII. FFXII had a long history of being delayed for a lot of strange reasons that no other company would ever have claimed to be a reason, including one of the key members of the development team getting sick, causing development to slow to a halt (if memory serves)a few times. What we ended up with when the game finally released, as the PS2 era was just on it's way out the door, was a vastly different sort of game then we had seen before. Coincidence? Probably, it's tough to say this far removed from it and from a series where every game is different in it's own way.
Any way, the sudden rise of internet swaying may not be the *entire* reason, but I feel it's safe to say that on such turbulent and uncharted waters of that time, especially for Square-Enix and all it had, and was beginning to, endure, they tried to take the safer route, which meant leaving a lot of fans to drown.
Here's the problem, and the problem that Jim probably ran into, not knowing what kind of trouble he runs into while researching his topics: the internet isn't as good at cataloging and retention as it claims to be. You look up something from that far back, and you'll likely not find a single word said from back then, if you even find anything at all, but a bunch of after-the-fact crap that was posted as far back as just a few years ago spoken from nostalgia, because those sites have updated this, or had to make room on their server for that. Even caches from that far back are sort of hard to come by.
There may not have been anything Jim could do to find out exactly what people were saying that swayed the industry so hard in this area, short of asking people who were in the industry at the time --but many of those people, likely still employed in it, will possibly be toting some hind-sight company like, because, well, it's easier to remember what was beaten into you then it is wasting time trying to remember what a bunch of any idiots on the internet said about something that doesn't really matter to you any more.
I also couldn't possibly come into this video expecting that he'd comb hundreds of ancient comment sections and forums to amass even the slightest imprint of what people were feeling at that time --that's something that had to have been lived through in the moment it happened, and remembered for what it was. (In otherwords: people of the far future are going to have a shite time trying to figure us out.. Like Liara trying to figure out the Protheans)
It's not exactly like it is today, where companies are still doing the same crap they did 6 years ago, because they figured out that feeding us the same game-thing every year, which fuels the same things said every year (with diminishing returns every time it's repeated), is better business to them then new experiences -which is a whole other topic all together- and leads to being able to relive the same sentiments every year, pretty much without fail.
(*and about this -this is also where the rise of more and more 10hrs or less games came from. People made it very clear during that near-transitional period, that they didn't want to put in huge amounts of time into games -usually stating that they didn't have the time to do that.. Fast forward to today, and people largely seem to slide in the other direction, saying that if they can't play a game for some untold amount of hours past 10, that they can't justify the game or the price of it.. Funny how that works out..)