If you consider an increasingly wealthy and proportionately small property owning class accumulating more and more wealth over generations then yes, it's a good idea.
I see your point. But, actually, no, not necessarily.
The idea of the structure would be to encourage parents to pass assets to the next generation earlier rather than later. But of course you can't easily do that to the extent if your assets are largely represented by the house in which you live.
So one possible result of such a policy could be to encourage parents whose kids have flown to downsize. Right now the tax system discourages that; you are encouraged to leave wealth locked up in your PPR, where capital appreciation is untaxed, and you see the larger-than-you-need house as a safe, tax-favoured and still accumulating asset which will shelter your wealth until you die. The downside is a CAT hit for your kids, when you die.
This system give you an option. You can reduce the CAT exposure by passing some of your wealth to your kids now and benefit by moving to a house which is better suited to your present and likely future lifestyle.
Of course your kids may promptly reinvest the wealth in other housing stock. But even if they all do that, that's not a greater concentration of housing wealth in this class; at worst, it's an unchanged concentration of housing wealth in this class (albeit a housing stock that is better allocated to the needs of the people who live in it).
And, of course, they won't
all do that with
all of the money. Some will use it for other purposes — capitalising a business, reducing their own borrowings, paying school fees, whatever. So the net effect may be reduction of the concentration of wealth in residential property, rather than an increase.
You could object that this does nothing to encourage the redistribution of wealth to people who are never going to inherit it. And that's true. But, then, the existing system doesn't do much to encourage the redistribution of wealth, does it?