Seem, I always defended the game just based on "linear isnt bad", not really thinking about the reasons why its linear.
Ive also always been confused why FFX is well liked despite... also being very linear up until it opens up at the end? But XIII got memed for hallways???
If you really break it down Final Fantasy has always been linear, in fact linearity has always been one of the big distinctions between jRPGs and cRPGS, but with the backlash to FF13 we learned just how valuable getting a couple of screens to run around and talk to NPCs is. FF13 feels very one note because moving through a dungeon fighting monsters is just one of the many notes that makes a good RPG, and it stays on that one note for a very, very long time.
The way you interact with the game's world isn't actually all that different from how the PS1 games played outside of the battle screens. It's just when you strip away any player agency and freedom the feeling of a grand adventure fades away very quickly and you're just left staring at the clunky gameplay and barren game world for what they are
While the earlier FF games were also linear you had to find your way to the next plot progression point yourself and there were towns and an entire world map full of optional stuff to get lost in on the way, which made continuing the story feel more like an active decision on your part