Paint can be poorly applied also....so like many jobs...it can depend on the human factor more than chemistry.
There are different grades of gel coat from what I understand.
It is considered easier to paint so it is by far the more common recoating method....but it will be interesting to see in 10-15 years as more refinished boats finish out their second lives.
This is from the Bertram 31 site (a group with a long history of top notch boat refinishing)...
"The resulting finish and the nature of the gelcoat will far exceed a painted surface in terms of longevity and repair ability, but you'll see why painting is the less expensive alternative. Gelcoat is less expensive in terms of material costs, but that is outweighed in terms of labor costs... Over a 20 year period the gelcoat becomes more cost effective, especially when compared with Awlgrip on topside surfaces since there would be at least 1 if not more re-paint jobs needed. "
https://www.bertram31.com/proj/tips/re-gelcoating.htm