This is happening in california. In fact there are three current situations: 1/SB9 cutting R1 lots in half 2/ ADU laws, which let you build up to 3 homes/units where there was one and further, can be combined with SB 9 3/ AB2011 which lets you turn defunct strip malls into housing

Honestly, this plus things like PermitFlow make me feel like we will be able to build enough. The issue will be making sure the housing is affordable rather than expensive and empty.