It's simple. Recycled storylines and same old roles in both of these movies in which audiences got bored of. Times were involving in the late 90s and some directors struggled to adapt hence using old stories and formula in their script in the early 00s.
AMALL is the worst movie of Hrithik but Ameesha who's one of the actress gave a horrible performance hence the worst part of the film. Their chemistry was boring and had no feel to it like Kaho Naa Pyaar Hai. Jeena Sirf Mere Liye is one of those C grade movies from Tusshar Kapoor who had no star quality not even 1% of his father Jeetendra had in the 80s.
The songs were terrible in both films but this one from AMALL is excellent which was shot in Canberra, Australia. There was a time where I was fond Hrithik in the 00s and still like him to this day.