Yes, I think around here the Air BnB owners had two really good summers due to the reduction in people flying/taking foreign holidays. But the downside was that because they'd turned all the cheap accommodation into Air BnBs, local attractions/restaurants etc were struggling for staff so visitors had a less good experience, and potentially won't return. This summer was still busy, but I agree less so, and as you say, next summer more people won't have holidays, or will ditch their cheap weekend in the UK and just have one holiday etc. A lot of people do Air BnB on a residential mortgage, too- and I think at some point, someone will clamp down on this.
Around here, they won't get many bookings over winter, but will probably need to run the heating etc on some occasions to help maintain the property, so increased winter costs, too.
I agree about landlords, too, and my understanding is that they can only raise rents once a year- so if they went for an increase in, say April, which now won't cover their expenses, then they're presumably in a very difficult situation. There have been a few threads on mumsnet posted by landlords who are making a loss on certain properties.
Anyway, my perception is definitely that some of these properties are now being sold- there's quite a lot of property available in the local area, which given it's a rubbish time to sell, and arguably even more so in this part of the country is interesting. And some really cheap stuff on the market which wasn't there at all in the spring/start of the summer.
Some places are definitely getting snapped up quickly, but those which need a bit of work or are a bit "quirky" appear to be sticking around longer.