My sense is many people, even educated and with solid careers, are seeing renting as a longterm prospect, and making peace with that idea. It is a critical mass phenomena. Although many individual condo owners rent their units, I think that longterm renters will prefer the security of tenure and professional management of a large landlord.
I hope the likes of Ed Sonshine move fast on their plans for more rental housing, and make sure there are a lot of 2 bedroom or bigger units (although many new 2bdrm units are quite compact).
here is a 2014 article of Mr Sonshine's vision for rental housing --
http://torontolife.com/real-estate/edward-sonshine-riocan-rental-housing/
Although many families don't need their own car in downtown Toronto, I think having a storage locker for each unit would be a good idea, perhaps in the basement, along with bike parking and limited carshare parking. Renting storage elsewhere can be a pain. Finally, it would be great if the new rental housing is built adjacent to attractive neighbourhoods with lots of single family housing, established businesses and good schools (e.g. The Annex, Seaton Village, Dovercourt, Dundas/Bathurst, Bloor West Village, Little Italy) -- long term renters, especially families with kids, especially want to live in these kind of hoods rather than the CityPlaces of the world. The potential for Bathurst and Spadina corridors from Dupont to Queen is big, as is along Dupont, Bloor, College, and Dundas (I'm sure there are others -- these are the areas I know best). Construction standards that allow wood-based mid-rises may also help make the economic case for upsizing smaller parcels along these corridors. Unfortunately, most of the purpose built rental buildings seem to be much bigger, so I don't know if the REITs will want to build the smaller buildings.
Finally, allowing homeowners to build more laneway housing, done sensitively, can add much needed rental stock.