Except that neither Gatineau nor Ottawa is interested in doing so. Which is why Ottawa proposed turning it into a bike path.
This is aside from the whole random takeover of a rail corridor justified by specifically federal rules. Imagine for a second, there was some rule that said if the TTC wants to abandon a track, you can buy it and then force the TTC to let you run your trains on the entire subway network. Sound crazy? That's exactly what MOOSE is proposing here. They aren't buying the bridge for just the bridge. It's because they can then force the Trillium Line and other rail corridors to be shared, as per their interpretation of federal laws and regulations.
In any event, all I'm suggesting is that the city should get on with the process. He says he has money to buy the bridge? Alright, let's see his investors actually put their money where his mouth is.