A lot of teachers are shielding or have vulnerable family members. A lot of students are the same. While we have distancing rules it's not feasible to open, and not safe.
I have two preteens and am fortunate that I can work from home, and I do understand it must be very difficult for people who need to go out to work. But I can't see how schools could open safely at the moment - say they have only 2/3rds of teachers able to come in, and say they have to limit class sizes to - eg, 15 - then it's not doable logistically!
Plus a lot of children wouldn't go back, so the school can't start teaching new stuff as lots of students would miss that and they'd all be at different stages.
The online learning thing won't work either - as some children aren't doing any work (no parental supervision or zero engagement) and some don't have easy access to tech - whereas others are keeping on top of it. So it would be hard to expect all students to have the same level of learning when they do eventually go back.
I think we all have to accept these are unprecedented times, and sadly, some children's learning will suffer. Once things return to some semblance of normality I hope schools will be able to put things in place to address the gaps - but health has to come first, right now!