Dishonored 2 reportedly sold 2.5M copies. Not sure about Prey. That may be too small of a market to support a full-blown AAA title with latest/next gen graphics and an army of playtesters to make sure it's polished and bug-free. But it shows there's still significant demand for this type of game. The question is how to make them financially viable. Things that have been tried so far include tiered pricing (special editions etc.), DLC, spin-offs, loot boxes/upgrades, microtransactions. Those are all about how to squeeze more money out of players for the same game.
But what about making them cheaper? Would fans still buy them if they had circa 2010 graphical detail and some lack of polish? Another idea that's been discussed several times but never really tried is episodes. Eidos Montreal was going to try that with Deus Ex, but unfortunately made The Fall a mobile game, hoping it might reach a bigger audience, but the opposite happened. Personally, I'd be willing to pay $20-30 for 10-12 hours of new content every year in episode form, but I might be in the minority.
And now we have Deathloop, which I'm hoping is like a short imm sim, except designed to be replayed a lot. We'll see how it goes.