Uncompressed 1080 is already approaching the eyes resolution limit, when viewing it in a living room environment. 4K is close to the monitor usage limit.
The reason that 4K seems better is often down to bandwidth and colour depth.
There’s zero benefit to an 8K TV. An 8K monitor might be useful, but is still well into the diminishing returns curve.
There’s still some ground to be made up with colours and frame rates, but resolution is effectively maxed out already.
Ironically, this is (partially) why government social support services originally started in England. Back in the Victorian period, the rich realised it was cheaper to pay a bit more tax to keep the poor fed, than pay for security to stop them being robbed. It was also cheaper than locking them all up.