I don't see it either. They're already about bottomed out on what is practical for mobile use frequency wise. I think the end game was to try to combine stations to lower broadcast costs while continuing to sell to pay TV (if it exists by then), or through network-centric streaming services like Peacock for NBC, but I also don't see 1.0 going away.I kinda think the end game may be to use most of the ATSC 3.0 spectrum for non-TV uses (e.g. datacasting services contracted out to other companies, including perhaps auto manufacturers). I'm a bit skeptical that there will ever be sufficient consumer adoption of 3.0 tuners to allow them to shut down their 1.0 broadcasts.
What I think will actually happen is OTA and the networks and affiliates will continue to fade away to lower and lower quality content, eventually just being a repository for low-grade re-run and syndicated content, kind of like the subchannels are today. If we're lucky, they'll keep a little bit of content on OTA to try and upsell to their network's streaming service.