The only locals' dive I visited back in September was Emerald Island. I went there in the afternoon and it was surprisingly busy--to the point where I turned around and walked back out, given the close quarters in there. I came back at 11 pm and things were quieter, but the place was by no means deserted.
The J-Nug is right smack dab in the middle of the neighborhoods that have been hit hardest by the coronavirus. Skyline and Joker's are a bit more isolated. I don't know if that has made a difference in how they've handled reopening. Joker's is a Boyd casino, and Boyd staggered their reopenings, on the premise that they didn't want to cannibalize their own business.
Fiesta Ratso is a case in point. It's right across the street from, and directly competes with, Texas Station. I imagine that Stations calculated that there wasn't enough business to keep them both alive. Plus, with its cheap food, small, inexpensive hotel, and good, low-limit gambling, it wasn't exactly in the Bellagio category as far as revenue was concerned. (Of course, neither is the Bellagio right now.)