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.
I wouldn’t go for “free”, that would lead to a lot of abuse of it. We only have so much capacity right now. A 90%+ discount on current prices, definitely.
I rarely use the trains right now, mostly down to costs. It’s so much cheaper to drive.