I'm sure they'd like to and it's in their long-term plans. They'd make a lot of money serving N America, because of the exodus of intellectuals etc after the revolution, there are more (for instance) Iranian doctors practising in the US than in Iran. Same goes for many other professions (engineers).
MEA want to open a route from Beirut to Toronto and Beirut to New York City. Same applies, huge first generation expat community.
Although "VFR" traffic (Visiting Friends & Relatives) isn't very lucrative, not many people can afford business class for a trip home to see their cousins and I don't think there's much trade between Iran and N America (or Lebanon, maybe a little more but not much). No tourism to speak of from either Canada or the US for either Iran or Lebanon. MEA would be better off reopening flights to Brazil, where there are strong trade links and more Lebanese there than in Lebanon.
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz