You are assuming Starfield will be moddable. Fallout 76 wasn't moddable, otherwise its problems would have got patched by the community. So if they implement some kind of always online mechanism like F76, Starfield won't be moddable.that's been fixed in f4 with a 10kb mod patch, and 76 already has it incorporated
Also consider their claim that the game will have 1000 fully visitable planets, which implies that either the game will be 300+gb in size or the planets are stored on a server, and so you need access to the internet at all times.