Do you think there'll be opportunities to start terrific technology companies in Toronto ~5-10 years down the line, when "everyone moves back"? Especially if they pay better?
There's always the opportunity. You could start a terrific technology company in Toronto (and stay there) right now, but you'd be an outlier. That said, I think it'll only take a few high-visibility 'anchor' companies to seed the city and start pulling people back in. And that could very reasonably happen in the next 5-10 years.