Developers won't bother with this. Even 8k Performance requires 4k NATIVE image to work with, using lower base resolution won't look very pretty.
There is no target audience for 8k so outside of few hardcore developers (like PD) no one will care.
8K is the new 4K.
The writing was on the wall when Epic did an entire demo around UE5 and 8K before the gen even started.
They will no doubt be updating Fortnite to 8K because they always want to sell what their engine is capable of.
Other UE devs will be able to easily follow suit as it is built into the engine.
Sony of course are pushing it, they have TV's to sell, and not to mention they also worked on the UE engine enhancements to support 8K, and we also have GT7 as a shining example.
Ubisoft will likely follow as well, particularly the Rainbow Six team as they are always deep into deploying the latest advancements.
RSS was one of the first/few to incorporate 120FPS.
No Mans Sky, goes without saying, they love their updates.
Indies in general can push 8K, they have plenty of headroom so it is a non-issue.
There isn't that many devs who won't opt for 8K, as I said it is the new 4K and devs will use it as a selling point to show off how amazing their games look.
The target audience is all gamers, even if you aren't on the bandwagon yet.