the only reasons i can think of are the ones i mentioned earlier... all the corporate elite around toronto usually snag up all the seats before anyone else can buy them, plus they're overpriced like everything else in toronto.
plus toronto is the biggest city in ontario, and that includes ottawa. thing with the ottawa area though, is that montreal is also close by, so they have some choice that doesn't require buying a passport and spending 2 hours at the border on top of the 3-4 hour drive each way.
in all honesty, i think the only two viable places in ontario for a new team would be toronto or hamilton.
don't get me wrong, it would be nice to get the jets and the nordiques back, but they would have to either remove dead southern teams or expand, and expansions require massive scheduling changes to accommodate, even moreso than moving a team or two.