All the broadcast stations are 720p or 1080i. Fox and ABC are 720p, NBC and CBS are 1080i (although I think some CBS affiliates are 720p?). I'm guessing some local stations may have slight variability.

The difference in 720p vs 1080i for broadcast to the end user is nothing. The progressive nature of 720p more than makes up for it being a smaller line count. Additionally, if you're watching any over the air broadcast, its uncompressed, which will likely be a tiny bit better than your cable/sat feed.

ATSC 3.0 will eventually allow 1080p and 4K, but its actually a LOT more complicated to do those resolutions than it appears from the outside, especially for retrans from cable/sat companies