The pandemic will probably be over in a year, though, so at least in the USA, I don't see a great future in the near-term for mid-40Fs outdoor dining.
I grew up in the South and live in the Pacific Northwest now. I think you see a lot less outdoor dining in the South not because of the winters but because of the summers. It's so hot that eating outside is miserable half the year, so restaurants aren't physically designed for outdoor dining during the couple of spring and fall months when it would be nice.
This is wrong in my experience. There are hundreds of restaurants equipped for summer dining [1]. Lots of restaurants have open rooftops, patio seating, open-air "fireman"-style garage door walls, etc. Pretty much every BBQ joint and taqueria is outdoors.
Outdoor eating is very popular in the Georgia summer.
Winter is going to be very difficult for restaurants. If they don't adapt to serving meals outdoors, they may not survive.
They're going to have to change a lot to create a comfortable environment for patrons. Fire pits, heaters, warm dishes: soups, stews, ramen, pho, pastas. Warm drinks and heated cocktails. All of this while maintaining safe social distancing.
I've already seen a number of restaurants and bars make the attempt. It's pretty ingenuitive.