BlogTO has a large number of "then and now" photo series you can have a look at for comparison if you're interested.
http://www.blogto.com/city/2012/05/what_queen_west_used_to_l...
Toronto was reasonably spread out.
The Canadian economy is addicted to 'new construction' as a form of growth + plus mass-scale immigration. Without it, the GDP numbers would not be good. Granted - the GDP/capita numbers would be just fine, so the choice is ideological.
Toronto opened up it's downtown to residential construction and that has been most of the change: massive residential towers (or even smaller ones) closer to downtown.
Of course - the endless construction of identical looking homes for 100Km in all direction continues unabated.
Driving North out of Toronto now - it goes on forever: identical homes, a Timmies, a Starbucks, a Home Depot, a TD Bank, another batch of the same homes, a Timmies, a Starbucks, a TD Bank - reapeat ad nauseum.
I think the expansion has largely been a disaster and we'll look back on it mostly as an economic trick to fill as many homes as possible in a short period of time.
SF has:
A) Earthquakes B) The Bay is a hodgepodge of cities. TO is mostly one big city under the same management. C) SF has quirky and specific views of 'how they ought to be'. Oddly conflicting at times.
There's plenty of geography around the Bay - there's no reason that SF 'has to go vertical' while the other areas don't.
Too much blame on SF.
If it's safe to put 25 story residences in SF surely it is also in Palo Alto and Freemont etc..
Or maybe tech could find another hub?