The only way the Saddledome would get saved is to have it re-purposed, which would involve heritage designation and a lot of public money and likely a private developer. What happened with Maple Leaf Gardens is pretty cool
So these things can be effectively re-purposed if the money and will is there. Convention space, movie theatres, retail etc. However you're talking about a couple Peace Bridges worth of $ in order to save the outside of an obsolete building.