I thought it was largely the fault of upper management. There was some guy in charge of Square who everyone online thought was a joke. He stepped down or was fired like a year or two ago. I never paid much attention to the politics but when discussing my own hopes that things will improve in future and FFVIIR will come out on time, someone pointed out Square is under a new guy and things are looking up.

But why can't the fanbase be changing again? Maybe XIII was the first FF for a lot of people and they liked it and it's mostly us old fogies who are raging at the youngins for having terrible taste. It seems very likely a new generation of gamers grew up with the XIII Trilogy and will also grow up with XV.