I don't see how Final Fantasy 13 bombing would make Square Enix do anything but go into defensive mode and basically milk their properties even more. If you don't like the last couple of FF games then so be it, there're still plenty of other games they make that are different from what the FF series is now.
As for spin-offs, etc, I don't think that has anything to do with the production values of the games. I mean there are spin-offs for Dragon Quest and they even announced DQX before DQIX has even been released.







