Not an ecosystem issue at all. There's no "yet". Linux computers even on the very low end are already perfectly capable of playing 4k Netflix videos. You can easily prove this to yourself by downloading one via torrent (you can generally get exact stream rips with DRM removed if you want). Netflix just won't send UHD streams to Linux users. That's a political choice, not a technology problem, and it's easy enough to get the media elsewhere DRM-free if it's that important to you since Netflix evidently specifically does not want Linux users as customers.