In much of the west, it is still a duopoly as far as TV and internet goes.
Shaw has a non-compete pact with Rogers for cable TV and internet, giving Shaw the west and Rogers the east. On the telephone side, BC and Alberta have Telus, Saskatchewan has SaskTel, and Manitoba has MTS. I don't know if Telus and Bell have a non-compete pact or not, but either way they do not compete head to head. I do know that Sasktel and MTS have at various times had a relationship will Bell, and certainly all of the telcos share their network and wireless spectrum.
The only arena where you see multiple telcos or cable companies competing with one another is in the cell phone market. Even there, it is mostly just Rogers, Bell, and Telus. Each of them operating multiple sub-brands, each offering the exact same thing as the competitors. Shaw bought spectrum and was going to enter the cell phone market, but unfortunately decided against it.
I suppose you could count the Satelite TV providers as well, which include two companies owned by Shaw and Bell. Another duopoly with a cable company vs a telco.