I would agree with you in that if Starfield has any longevity, it would be because it would serve as the foundation for mods rather than on its own merits. But I disagree that it could stand on its own as-is.
I’ve played about 40 hours so far on a Series X. It froze on loading twice in that time, but otherwise I’ve had no performance problems. I even tried remote play streaming from my Series X to my PC and it worked well also.
That said, Starfield is fine. It’s not great- I don’t think it would be considered GotY even if BG3 and TotK hadn’t come out this year- but it’s otherwise solid. If you like the Bethesda formula, Starfield plays it absolutely straight (for better or worse). The usual critiques of Bethesda games in general apply- it has that look of a Bethesda game, the NPCs have the facial animation range of a post-botox Barbie, Radiant quests abound, the exploration gameplay loop is pretty shallow, etc.
Don’t get me wrong- there’s a lot it could do better, much of which other games already do. It’s a sci-fi fi version of Skyrim, and that’s good enough for me, but it probably won’t live on in the gaming zeitgeist.
Yes, if you’re selling millions of units. But if you’re buying just one, $2-$5 probably isn’t going to matter to you. Not many people would buy a game at $68 they wouldn’t buy at $70.
Optical discs are dirt cheap. This old answer from Quora says physical media (disc, case, artwork, inserts, etc) accounted for $2-$5 of the cost of a game.