You can Google about ATSC 3.0. There is lots of hype that it could include 4K, but the reality is that few if any stations will ever us it. They will use the extra bandwidth to cream more channels in. There is even a proposal for audio-only channels, and up to 50 channels could be put in one frequency, giving a bit of a SiriusXM like capability.
The BIG killer could be encryption and Digital Rights Management (DRM). Sinclair and some of the broadcasters have forced the standard to add in encryption capabilities. The encryption keys must be hard-coded at manufacture, so you cannot do a firmware update to add it. Further, encrypted channels may require the TV/adapter box to have an Internet connection so that the key can be checked to see if it's been revoked.