I can see schools going back after half-term, probably not all years back at once.
At work, you don't get to go inside the buliding until your temperature has been checked. Schools could do the same. They could also work a shorter day, and use gyms and halls as classrooms for extra space. I know its not great to lose exercise time, but I think it is acceptable, given the circumstances.
We can't wait until the virus has completely gone (will it ever?), or until there is a vaccine. It's a least worst solution time.
The pressure to send kids back is building from all side - look at some of the threads on here. People are getting stressed and angry,- some schools and parents are clearly managing far better than others. In the press, there's talk of unbridgeable attainment gaps developing between the better off and the most disadvantaged, - some private schools are shaping up to to go back in June and/or teach into the summer holidays. If it carries on along those lines, it will be hard to keep all state provision closed.
As other have said, lockdown was really to slow the spread, and buy us time to sort out the Nightingales etc. We can't hide forever.