Yes, for real value, quantitative studies might be impossible.

Rent just means income without work or exchange. If you want to account for real estate, you can't wave rent or ground rent in the Marxist sense, because expected rent during depreciation plays a part in determining the price for things like land, which don't have an inherent value, because no labor is used to produce them.

I was manly interest in the impact on revolutionary potential in the core.

Edit: Oh, sorry, you meant the premise of revolutions, hence no more rent. Yes, of course.