The cost to construct brand new housing is considerably under US$100k per person where I live (US smaller coastal city, considering a smallish walk-up building), if you exclude land costs. At current interest rates, that could be financed at around $200/month, around $1/hour of full-time work.

In reality, a unit that costs $200/month in construction financing might cost ten times that to actually rent. Most of that reflects the cost of acquiring the land.

In principle, there is no reason that land needs to be particularly expensive in a lot of the places where it is. My guess is that a lot of the current price reflects land's status as an investment vehicle, which is largely an intentional policy choice (albeit one that might be politically infeasible to substantially change).

Either land keeps its value, in which case income and capital gains tax are no longer needed as government income would be enourmous

Or land loses its investment appeal, and is instead just the competition between different people in how well they can use it

It seems crazy to me that there are acres of land in Manhatten than are used for street level parking

At the same time, it's hard to fault buyers for this. Commuting sucks (what price do you put on 2 hours out of your day?), and the difference between a "good job" and an "okay job" can be an order of magnitude in income these days.