I don't think you can go back once you cross that line. GaaS is like a disease with no cure for dev teams. Once you change the culture for a company and start pursuing MTX, loot boxes, co-op, content updates etc its pretty much becomes permanent.
Seeing what happened with Fallout 76, Youngblood and the new Arkane IP...I think its safe to say the singleplayer only future is dead at Bethesda. The Bat signals are all turned on for Wolf3 development. Even DOOM Eternal is pushing some stupid 2v1 mode.
And worst of all Starfield + Elder6 will most likely have online/GaaS mechanics of some kind
RIP #saveplayer1