How is value for one generation balanced against subsequent ones.

I don't know actually. By market regulation? By ensuring new housing isn't a PITA to build and telling NIMBYs to fuck off? You'd also need to regulate the other way. Ideally a maintained house wouldn't have its value changed that much over time. And it would be adjusted to inflation.

if you pay a mortgage like most people do over 15-30 yrs, you're paying something on the level of 150%-200% of its value.

Yes and your net worth accumulates 50%-66% of what you pay. That's better then the 0% for renting. AND you don't need to complete the mortgage to sell the home and reclaim that stored wealth.

And yes housing should be affordable. I'm saying all this within the context of some kind of free market economy with some kind of private property. Being able to add most of your home payments to your net worth is very helpful in the long run. Especially if you need the Monet, you can switch to renting. Again, ideally, that would be the same cost as a mortgage, as the landlord would be using that rent to pay down their mortgage or whatever.