That's actually what I was insinuating. RPGs peaked in popularity during the fifth generation and have been on a downslide ever since. With the rising cost of development the marginally popular game franchises are getting pushed out of the market (see: Shadow Hearts for a recent example), which in turn leads to less innovative games, because you can no longer afford to gamble on a weird idea... unless you're tri-Ace, apparently.
Yes, SH died, but that certainly wasn't for financial reasons; sounded more like a falling out between the design team that made the series and the publisher that holds it copyright. Last I checked most of the other niche series (Suikoden, Wild Arms, Arc the Lad (sadly), Valkyrie Profile...) are still chugging along well enough.
I don't think fifth generation was the peak, either. (assuming you are referring to the PSX gen). I mean, look what happened in the sixth gen...
-Final Fantasy and Dragon Quest continue to make huge sales. Shock, awe. Actually, DQ finally breaks into North America with 8...
-Kingdom Hearts! Hello, massive million-seller.
-Star Ocean goes from a niche series to the bigtime.
-Series like SH, Xenosaga, and N1 establish themsleves (even if only N1 made is still alive, they were notable and pure Gen-6). FE comes to North America.
-SMT becomes less completely irrelevant.
-Suikoden records its biggest-selling game.
Now yes, you can point at Breath of Fire dying (not that Capcom ever seemed to care...) and WA becoming more of a niche series. And yes, no
one RPG from this era was as popular as FF7. But aside from that I don't see any sign that jRPGs have been declining.
That leaves this generation, but the general clusterfuck that is the PS3 has caused some confusion for the genre's designers, and it's too early to judge how this will affect it long term.