Ultimately the FCC doesn't care. Their current focus seems to be to eliminate virtually all of the safeguards and rules to allow TV ownership to do whatever they want. It seems highly unlikely they're going to suddenly grow a backbone when it comes to DRM on ATSC 3.0.
If they really wanted to move on this issue they've just been handed a golden opportunity. They could tell Nexstar that if they want to merge with Tegna (which requires the FCC to change their own limits on station ownership) then they have to commit to broadcasting their ATSC 3.0 feeds with no DRM.