A second team won't happen. It's actually been tried a couple of times and both failed early in the attempt. It ends up being a non feasible business decision.
Aside from the cost of a new franchise, the owner would also need a new arena acceptable by the NHL. One of the previous attempts was looking at the arena in Hamilton but it was rejected by the NHL. On top of that, a team in the southern part of Ontario has to pay fees to both Toronto and Buffalo for invading their territory and that would run close to $200M plus each. As well, a new team would pull some fans but would always be a second team: like the Mets to the Yankees, Clippers to the Lakers, Islanders to the Rangers ... a team that would always run second in revenues as well. On top of all that, MLSE owns all the feasible downtown areas for an arena.
So a new team owner would have to pay for a new franchise, plus build a new acceptable arena in an area in the north of Toronto that would not have any decent transportation to it, plus all support staff and farm teams needed for a new franchise, and after all that, would still be a secondary team for the area. For a new owner to do it, it would require well over a billion plus just for the minimum to start and would have a lower revenue stream that would take decades to recover the initial capital cost after yearly operating costs are factored in. This has been discussed to death many times in the past, and it was also in The Economist a few years back. It just doesn't have good enough business criteria to do it.