To put it another way, why not raise taxes to $1M/sq.ft.? $1B/sq.ft.? If if were true that it wouldn't be passed on to tenants then you've found the magic money tree.
A property tax affects all square footage of apartments quite equally, which is very well correlated to rental prices, so a property tax is roughly equally a rise in all landlord's costs. So in the very few housing markets where rental prices have fallen to near the cost level, and there's very near zero profit in renting, property taxes could easily cause a rise in rents.
However when switching to a land value tax from the current property tax system, the incidence is quite different than a broad property tax increase. Some landlord's taxes fall quite a bit, some landlord's tax bills might increase.
And then all landlords will see a surge in vacancies, and not all landlords are able to tolerate paying LVT on empty units for very long before they're forced to drop their rents back to the actual market value.
> why not raise taxes to $1M/sq.ft.? $1B/sq.ft.?
Same reason why landlords can't raise rents to $1M/sq.ft or $1B/sq.ft: because nobody in their right mind would pay that much.