A Manhattan where the property owners pay huge taxes to the government (because that's what it would take the drive the land value to zero) would still be an extremely expensive place to own property. This might be a good way for the government to raise revenue, but it's not really a "cheap land" situation. It's one where the government is effectively the landlord and everyone pays high "rents" to the government.
It's plausible that such a scheme would lower the cost of living in some places when it's due to speculation, by popping the bubble. But it doesn't lower the cost of living when it's due to the fundamental value of owning property there.