Toronto would be a great first entry for Jet2 into North America.
757 can get there, only problem would be the cost, as the aircraft would have to be ETOPS rated. That means you need more engineers than are all ready available. e.g. any work is needed to be done on both donks, a different engineer would have to do the work on each donk. One engineer can't do the same job on each donk.
That is only one of many exsample that comes to mind.
I'm not saying it is not viable but the tag of low cost may not be a true reflectionin that situation. But I would personaly like to see it happen, maybe in a few more years.