I find it so frustrating that there is only 1 airline flying the SFO-YYZ route. Virgin canceled theirs in 2011 I guess because they couldn't make any money. But

I find it so frustrating that there is only 1 airline flying the SFO-YYZ route. Virgin canceled theirs in 2011 I guess because they couldn't make any money. But looking at AC fares, it's clear a single carrier is making too much money on this monopoly. How do we get free markets to work in a system like this? 50 passenger self-flying planes?