The incumbent telecoms generally refuse to peer domestically with independent ISPs and smaller transit providers that cheaper DCs use.
One ISP reported that Bell would only connect to them in Equinix in Chicago, even though Equinix has a PoP in Toronto. https://www.peeringdb.com/net/1550
This means if you subscribe to internet with the local telephone monopoly (Bell) in Toronto, your traffic to toronto[1-8].voip.ms goes through NYC or Chicago. Have seen some routes that add Washington DC to the mix too. A 5km trip made into several thousand km.
The incumbents even don't peer much at our big IX: http://torix.ca (they buy ports, but don't peer freely).
In a lot of ways, because the independents will peer with everyone and love IXs, your traffic often stays a lot more local in Canada.