To the north, competition from a huge installed base of last-gen technology, which is mostly good enough.
To the south, streaming services, youtube and cable. These let people watch whenever they want (nobody has VCRs any more) and they've offered 4k for over a decade.
To the east, the industry's dumb decision to build the 'next gen' technology atop a patent minefield, and load it with DRM. So if you manufacture this tech, you can face huge surprise bills because in implementing the spec you've unknowingly infringed on some nonsense patent.
And to the west, the commercial reality that showing someone an advert in 4K isn't any more profitable than showing the advert in 1080p. If you're a broadcast TV station when you up your quality everything gets more expensive but you don't make any extra money. So why bother?