Generally, the change would allow single-family homes. But it would not REQUIRE single-family homes.
A typical development pattern might be something like...
- all single family homes to start
- area gets popular (property value goes up), a few SFH are replaced with duplex or small apartments
- area gets more popular, more SFH removed, mid-rise apartments begin to appear, small-scale retail appears
Etc.
Of course, this requires that NIBMYs aren't allowed to control other people's property. And the zoning and codes that do exist are enforced so you don't end up with a SFH next to a gas station.
A typical development pattern might be something like... - all single family homes to start - area gets popular (property value goes up), a few SFH are replaced with duplex or small apartments - area gets more popular, more SFH removed, mid-rise apartments begin to appear, small-scale retail appears
Etc.
Of course, this requires that NIBMYs aren't allowed to control other people's property. And the zoning and codes that do exist are enforced so you don't end up with a SFH next to a gas station.