I'd guess nobody re-gelcoats a boat for appearance reasons nowadays, only if the existing gelcoat has gone defective and needs to be removed, and is paid under an insurance claim.
To re-gelcoat you first need to remove the old gelcoat, which immediately means a bigger job than patching, priming and Awlgriping the old. If you want to consider re-gelcoating, see if you can find someone to quote the work, if you do, you will lose interest.
I expect builders who Awlgrip new boats only paint those boats who buyers want a color other than the white gelcoat. Alwgrip or a similar paint is necessary if you want a good looking non-white hull.