That's the problem with Rockstar now, they got too comfortable and did not care to improve their games outside of ''muh details, cinematic animations and graphics)
SA was the last good GTA and was ahead of it's time in what it did, features in GTA we still do not have today.
While GTA 4 had a THEE best story, the gameplay was mediocre but it also had A LOOOOT of work put into it, we had the lost & damned and gay ballad of tony, fantastic storylines and ballad of tony also brought in new guns, new stuff, and better mission then gta 4, and GTA 5 was worst, mediocre gameplay and a awful story.
THE BIGGEST problem with GTA is the mission design, Rockstar is STILL using the same lousy ass terrible mission design since fucking GTA 3, it was good for Vice City & San Andreas because they were all on the same platform.
But for GTA 4 & 5 to have this sloppy ass generic mission design...just bad, every mission is a drive point a to point b, tail this car, escape cop, generic shootout scene, etc, etc, GTA 5 did it ten times worst with those generic ass heist story missions and a yoga minigame mission you were forced to do.