If you don't know how having a big house makes homeschooling easier than a flat, you haven't got much imagination. I've lived in both, and am so grateful not to be in a flat now. Less space means dad on a conference call has to share a room with one of the homeworking children, means the kids have cabin fever and no space, means your forever shushing them and can't do the indoor PE lesson or the downstairs neighbour will call your landlord again. Means nowhere to put things after muddy walks, means no bikes to get further out on your exercise sessions, means they're always next to the kitchen and complaining for more snacks, means 2 weeks of isolation is truly mindbending
I’ve lived in both too. I see your point about multiple kids crammed into a too-small space, lack of storage for outdoor things etc, but wouldn’t this have been a problem before lockdown too? Eg constantly shushing them because of neighbour downstairs, nowhere to put muddy things, proximity to the kitchen for homework, lack of bikes, not enough bedrooms; these are daily problems highlighted by lockdown not caused by it.
Space has its advantages but also means more cleaning, more chasing kids around trying to keep them in one place to monitor them, more going from room to room to check they’re working and haven’t slipped outside to play in the treehouse or muddy garden while you were on a call. It’s more expensive to heat, general running costs are higher, parents can’t risk losing their job(s) as they have bigger outgoings.
A SAHP could be just as exhausted as a parent juggling work with school. A mum in a 5-bed house with huge garden could be just as exhausted as a mum in a 1-bed flat.