They wouldn't when they realise that it is a cheaper alternative to existing satellite internet services, not cable internet. Also that it would have reception issues in urban and suburban areas which is why they are targeting rural areas.
Quote: ------
The CRTC requires telephone and cable companies to sell access to their networks to independent Internet service providers (ISPs) at regulated wholesale prices.
Nowadays they just look at other plans and say, nope, you're on something better than anything we offer now.
FWIW Fizz is the new hotness here. They have worse coverage outside of metros, cheaper base plans, zero phone customer service (problem for negotiating cheaper deals I imagine), and rollover data, which Virgin does not.