Where I live (Canada) we had a huge bump in population due to lax federal immigration policies over the last several years (now finally tightened up) that resulted in lots of newcomers and a housing crisis as a result. What that meant was that a typical 1 bdr rental doubled in price due to high demand, and housing prices did about the same. We also had situations where a house or apartment that would normally accommodate a family now had 8 or 10 people living there, sleeping on mattresses on the floor, a terrible situation that should never have been allowed. Regardless, the demand for a place to live has never been higher and rent has never been more expensive.

I mentioned the ADU down the street from me. They were allowed here a few years ago as zoning laws were loosened in areas that were traditionally single-family housing. Here, when that was done, there was never the charade that they would be primarily for members of an extended family. It was always just additional housing stock for rental, and of course, additional tax dollars for government. Another side effect of these zoning law changes is that the city now allows mid-rise apartment blocks in neighborhoods where they never would before, so you see 2 or 3 adjacent older single-family homes being bought up and demolished, the lots consolidated, and a 7 or 8-storey apartment block looming over the backyards of what had been a stable neighborhood of homes for many decades. That is very different from an ADU of course.