Greed is certainly a factor, so is laziness, lack of creativity; something SC is known for
That's true, there are lots of different types of sites though.
Look at what the prospective MTSA is causing at St Clair/Weston. Nothing about that land historically screams residential;
it's all employment lands, which until recently would have been thought of as entirely off limits.
Even if the edges were nibbled away at, the surrounding residential is all SFH.
Yet, here we are, looking at literally thousands of units, hirises/skyscrapers/retail etc.
*****
At the same time, we can look over at the Sheppard area between Bayview and Bessarion; what's being torn down?
Mostly single family homes, that are interior to the neighbourhood (away from the main street, which is Sheppard); along with some low-rise apartments, in favour of both midrise and hirise residential.
That's not the only location like that; there are several others, some even have explicit yellow belt zoning. That will change.
MTSA's in particular will open up a lot; but even without them, change is afoot in many areas.