No, it's not a tenable solution.
Neither is full-time online learning for a majority of under-14s. Only at that age and over do I think it's reasonable to expect the student to have the maturity and self-motivation to cope and crack on with that mode of education alone. There are still big online safety issues. And over-16 would apply to some.
For primary and at least lower secondary you are expecting more supervision and input from parents which, whether they work or are at home with caring responsibilities or for other reasons, isn't practical.
Access to home broadband plus suitable devices is an important issue but on top of that, you can't expect parents to sack off all of their necessary daily routine to follow a school timetable on Teams.
Homelearning for many will be doing their best to keep up with reading and a bit of other English and Maths. Some won't do anything, that isn't a criticism. I live in an urban area with my children attending a school that's just become an academy due to safeguarding issues and falling standards. Many families are just coping with keeping roofs over their heads, food on the table and clothes on their children's backs. MH and drug/alcohol problems too.
To be properly settled in a classroom environment, kids under 14 need to be in full-time. In my view the government are doing the right thing now keeping schools open, carrying out more testing in secondaries from January. They do need to get rid of the self-isolation for well children rule as that isn't practical any longer really. Certainly not if they're still saying exams and SATs will go ahead in just a few months time.
Or we close schools indefinitely but then funding would have to be diverted from schools to the home environment. Laptops, free broadband, something like the old tax credits system so one parent can stay at home or free childcare available for a single, working parent. Everyone accessing lessons from a central provider. A lot of teachers and other school staff out of their jobs. Not something easily reversed in a couple of years. And a seismic societal change that not many want. An increase in MH issues and, for many of a whole generation, a lost education.
I'm all for home education where parents decide on that but blended learning isn't that and just doesn't allow for the flexibility needed working in the home environment rather than classroom.
Schools need to stay open full-time.