In which case another developer will build them. Assuming the numbers make sense.
Either way refusing to allow apartments to be built because you fear they will be "luxury" is dumb. It just means that the only people who get to live there are the really rich who can afford a full-sized house.
Which is what you'd expect to happen in a free market.
Absent a reason, why would developers voluntarily choose to build an option that would make them less money?