One of the things I'm curious about regarding even gentle infill like this, which I love to see happening, is around parking.
It was interesting at a council meeting I heard where admin shared stats that even though population had decreased in some of our older neighbourhoods, fewer people per household, parking was a bigger issue than in the past because more people have cars versus maybe one per household in the past, now there can be 3 or 4.
So as these neighbourhoods increase with even this gentle density, what is it going to mean for all the cars on the street because that 4 plex with basement suites isn't going to have garage parking for 8 or more vehicles.
If we didn't have so many cars, this wouldn't be such an issue. But that is our culture.
For once, I believe that this is proof that the demand for housing doesn't necessarily depend on parking. A lot of this gentle infill is happening in areas where these new residents (which I'll guess are mostly younger families or recent immigrants looking for more central living, but with enough space for families) don't have, or want, multiple cars, for one reason or the other (financial constraints, lifestyle, etc.).
I understand it is anecdotal, but I know a few families who moved into some of these more centrally located infills, coming from suburbia (mostly north side) and one thing all of them had in common was that they went from having 2 or 3 cars to only one. One couple, who moved into a skinny house in Westmount, actually dropped both of their cars and now use Communauto whenever they need a vehicle, but they mostly bike or take transit.
Parking might end up being a short-term issue, IMO, in this situation. I believe that, in the end, these people with 3, 4 cars in a single household, living in central (ish) neighbourhoods will end up caving and packing their stuff to the outer suburbs. while people who are less car dependent will end up filling up the vacuum. I'd be willing to bet large sums of money that the Venn diagram between the folks with 1-car-per-person households and NIMBYs is almost a perfect circle, which means that as densification intensifies (and now with less power on the NINBYs' hands to be able to stop it from happening), we'll see a run for suburbia. My money is on this process being sped up by the influx of migrants from ON and BC, most of whom will probably be happy to buy/rent a skinny house, or a unit in a fourplex, townhome, etc, with 2x the space of what they could get in an apartment/condo in Toronto or Vancouver, for less money, and where they won't need to have multip[e vehicles (or any vehicle at all, sometimes).