Guess what, I played this not-so-Final-Fantasy game. I progressed up to right after the Henne Mines and it's been almost 3 months since I last inserted the CD into my PS2.
The reason? I got bored. Why? Same as your reasons above. You practically do the same things over and over again.
But I think I'll go back to it once I get bored with Resident Evil 4.