Most of the "faithful ports" are just releasing the GOG ports on Steam. The ones that are not, are mostly games from the wing commander series (so likely a lot of shared code and shared effort porting them), and FMV updates (which again, they probably just had to figure out once how they wanted to re-encode the FMVs)

Sega used to do these types of collections in the pre-AI era too.

Their promotional material and launcher (to choose which version of the game) seem to heavily reference how they’re using existing (named) community patches (on top of the optional new FMV).