It is a combination of many factors.Toronto is fully built up except for infill and redevelopment projects, so the supply of new homes (excluding condos) is minimal.The City is well run and attractive to businesses and immigrants.
Foreign investors, mostly Chinese, want a safe haven for their wealth and Toronto is marginally cheaper than Vancouver.The local, provincial and federal economies are strong, although not growing much in recent years.The banking system is stable and interest rates are still quite low.
The City has good infrastructure and more rapid transit development is forthcoming.
It is because of demand.Everyone wants to be in the ‘centre of the universe’.Nice housing is available cheaper in the outlying areas.
Well paid jobs are downtown.“Say Honey, let’s buy a house in the burbs and commute”.Then the first Winter comes.
Driving times explode to insane lengths, in the dark, in the snow, surrounded by crazy drivers both ways.GO trains are disrupted.Even the subway switches freeze.
Living in town suddenly looks more and more worth the cost.