Even then no, I build a 30 unit building, covid 22 hits, nobodies buying, I'm on the hook for 30mm / day. Nobody would even build with that risk. You'd have low density housing, single unit homes and massive traffic/pollution issues often associated with suburban sprawl.
Yes, 1m/day is hyperbolic, but if you put the constraint on the suppliers (builders, owners), and the demand is inelastic (you've got to live somewhere), then the outcome is to constrain supply for maximal benefit.
2) A builder can hypothetically continue "building"/renovating the units indefinitely until they have a buyer. Alternatively, nothing about this hypothetical scenario requires the original constructor to even pay the $1M in the first place - it could be deferred, or be another rate entirely.
Side note) Landlords/owners aren't suppliers, they are speculators.
Yes, 1m/day is hyperbolic, but if you put the constraint on the suppliers (builders, owners), and the demand is inelastic (you've got to live somewhere), then the outcome is to constrain supply for maximal benefit.