Shop around, buddy.
You can also always install multiple ride-hailing apps. Including the taxi company's own. There's also Lyft, who's considering a Toronto launch depending on how dust settles -- they've already sent a lobbyist to Toronto City Hall to scout things out. Uber is not the only game.
Inevitably, the taxi hail app will often not provide available taxis at moments during moments when Uber has surge pricing (e.g. during unexpected transit shutdowns, etc).
You can choose to wait longer for a fixed price ride (taxi), wait a few minutes for transient surge prices to end (Uber, Lyft, etc), take an alternate route (google map it), take the emergency TTC shuttle bus (TTC alert), grab a bikeshare (if in territory), grab a car2go car (if in territory), or just pony up.
All the above now all have apps, and some apps have merged maps that display multiple of above concurrently (e.g. Transit App supports BIXI integration, Uber integration AND car2go integration).
Many transit is providing publicly-available data feeds now.
Uber is, BIXI is, Google is, TTC is...
More third party more apps merge all kinds of transit (carshare, bikeshare, buses, trains, Uber) simultaneously onto the same map --
Transit App is one of them. It simultaneously shows the nearest bus, nearest train, bikeshare bike, car2go carshare car, nearest Uber car!
Telling you multiple options of getting home, on the same map. Hate the Uber surge price? The app's telling you alternatives like a nearby BIXI bike or car2go vehicle (supported in several cities; Toronto now partially supported).
And are you a programmer? Write your own app. Downloads the publicly available transit data and display something great with it. It's being done already today.
So, shop around buddy.