Silly premise. The future will bring us 8K, and heck, much better resolutions than that too. There are quite a few things leading to it not being popular *yet*.
1. Something needs to drive it, without jitter. That means whatever storage medium the movies/series are on, needs to have enough processing power to decode the video and ship it to the TV. This is less of a problem now in 2025, but my original Popcorn Hour box had problems with 1024p. And that was in 2015.
2. There need to be enough bandwidth, everywhere, for folks to actually be able to watch content over streams. Sure, lots of us have GB connectivity and fiber et al - but that's far from everywhere. Even in 2025. If you don't have enough bandwidth - why would you be interested in this?
3. Even Blue-Ray would not be able to store a movie w/o heavy compression, and what's the point of 8K if you have compression artifacts all over the place? A 2 hour movie needs 100G+ , and if it's not compressed to hell and back - probably quite a bit more.
4. Connectivity. You need to be able to deliver this over a single cable, which needs to be standardized. This might have happened by now - but it needs to be everywhere. Specially designed non-standard stuff won't cut it.
5. Pricing. Very few people will fork out $2K+ for a TV. I still don't even have 4K TVs as they were too expensive last time I refreshed my TVs. Next TV I buy will of course be 4K - as the prices are now OK. For 8K TVs to become mainstream, prices needs to become reasonable.
But we'll get there. We just need the rest of the "delivery technology", standardization, etc. to catch up, in addition to prices to drop. Give it another 10 years.