When we're talking about tiny proccesses happening multiple times on one display, it does matter. Ot at least it does with manufacturing yields that make sense.
In the cpu space, Intel has been struggling to shrink their processes to 10nm and 7nm and it's not because they haven't worked out an automated process to do this, it's that there's enough of a failure rate in the manufacturing process that they weren't happy with the profit margin they would get from selling them.
Smaller processes with more points of failure is going to result in lower yields. But if they solve it at 4k, it at least makes 8k easier. I can see a path where they make it a technology for ultra large TVs, like 80" and above maybe and look for new options in the smaller space.
