That's going to be the biggest contributer as time goes on (not right now though), as eventually all desired land will have been bought by what amounts to an oligarchy.
Honestly, land/homes should never be inheritable, and companies should never be able to own land altogether. Not that this would ever happen. The status quo is too profitable for the land/home owners.
Eh, nah. But, there should be inheritance taxes set at a level which prevents the formation of a "landed gentry". Unfortunately, the issue has been demogogued to the point that middle-class people (who won't have anywhere near the assets to be taxed, as in not by an order of magnitude) treat the idea as anathema.
The middle class is afraid of taxes that are "for the rich" being extended to tax them. And not without some reason - income tax was sold as "only for the rich".
Fixing the issue has been stymied for too long by each pointing at the others and saying "They're the real problem!" to justify inaction / rolling back fixes on their pet interest.
All need to be addressed.