Let's face it, Final Fantasy died as a viable art form with FF7, died as viable franchise with FF8, and died as a playable game with FF10.
FF6 was the last of the classic Final Fantasies, I still don't agree it was the best, but it was definitively the end of an era.
FF7, was unique all to itself, while in many respects part of the FF7-FF9 era, it was by itself truly the last viable masterpiece of the Final Fantasy series. While untraditionall it was intensely popular making it at the same time both traitor and savior of Final Fantasy. In the end it would be the harbinger of a new generation in Final Fantasy, but a generation that would never live up to its progenitor.
FF8-FF9 were awkward experiments that would have been forgiveable in hindsight, however with the franchise's failure to create another FF7 following them coupled with its descent into the gaudy emo-androgyny of FF10 and beyond, these two games, by default of their successors, became mere casualties of an era that never was.
FF10 was the begining of the artistic stagnation typical of modern Final Fantasy games, it embraced linear character designs, recycled archetypes and a simplistic yet "hyper glam" art form reminisent of FF8. Experimentation had given way to simplification and streamlining and with each subsequent game the series simply refined aspects and mechanics of the previous. Artistic experimentation in the series now ranged from the timid to the questionable.
As Final Fantasy games continue to emerge, it becomes ever more apparent that the talent lost by Square-Enix to Nintendo and Mistwalker over the years has severly hindered their ability to produce the games they once prided themselves on. Now the extent of their expertese seems limited primarily to cinematics rather than actual gameplay, innovation or story telling. And with the absense of Yoshitaka Amano's art and Nobuo Uematsu's music in the series now, many even question whether these games can be called Final Fantasy anymore.
The first indicator to us that things were going terribly wrong should have been FFX2 followed by the whoring out of FF7 through a meriad of spin-offs and ultimately a departure into an era where nothing was sacred.
I think the biggest reason people cling to Final Fantasy till this day is because there has yet to really be a JRPG to take up the mantle it once so rightfully bore. And as JRPGs seen to descend further and further into niches rather than main stream appeal, Final Fantasy may forever be a dying dream and a lingering remorse.