> they have no real infrastructure of their own
I think I know what you're trying to say here but this statement is not really accurate. They don't have their own last-mile infrastructure but they definitely have their own network infrastructure to support their customers.
Competitive providers (like Teksavvy) use the incumbent's last-mile infrastructure (the cables that run into all the customer houses or buildings), but once the traffic gets into the telco's network, it exits that network ASAP and the wholesale provider takes over and is responsible for setting up their own peering and carrying the customer's traffic beyond the telco that is providing the fiber/copper loop.
They're not just white-labelling the telco's service.
Also another small correction: TELUS only sells wireless in Ontario, but in Quebec and in BC/AB they are quad-play (wireless, Internet, TV, phone) just like Bell and Rogers are in Ontario.
And in fact Bell and Rogers out west are the other way around, they only sell wireless. Although now that Rogers has bought Shaw, Rogers is looking to become a national quad-play provider next year.