[spaceflunky]

>Well their kids could live in them

Unlikely. There's a very high likelihood the house will have to be sold, either to pay off debts of the deceased (or bereaved), or because the children already have their own lives going, or because they don't want to assume the tax burden, or simply because each child wants their share to do with as they please.

>or sell it and buy a different house to live

This is what's going to happen. All of these property will be sold. A very small percentage will be assumed by the children because of the all issues mentioned above.