I don't think this is a good solution. Where is the incentive for anyone to maintain properties anymore?

"Owners of valuable land would be forced to make maximum use of land with higher density rentals in order to make sufficient rental income to pay the land tax."

I don't see how this follows if all income is taxed at 100%.

The correct solution is to eliminate NIMBYism by eliminating the ability for homeowners to restrict the construction of new buildings so that new housing can be built. Rent control should also be eliminated, allowing demand to match supply.