Every form of entertainment industry follows a basic formula. Often not because it likes to, but because it's the only way to capitalize on people's enjoyment, which can be quite fickle. Movies, literature, music, anime... it's normal. Unfortunately following a formula only assures that you will sell your product to the general audience, not that it will be an exceptional or memorable product.
The mistake is here: some companies believe that throwing money at a crap product that follows a cheap formula will give them a masterpiece...all it does, and of this FFXIII is a prime example, is boost their sales thanks to publicity and hype.
Square-Enix may be a better company today that makes better games than it did before, but when compared to the old era's Square masterpieces... its new games are simply put to shame.