Forget about the CFL, it has been constantly dying for decades but those predictions never come to pass. Smaller, sure. The US expansion era was by far the worst era but I feel like it is remembered so fondly. Its succeeding in big markets like Montreal, Toronto, and BC. That matters. We don't need something capable of hosting the World Cup final, if the Grey Cup really does bring 50 Million in economic benefit the one in 2026 is pretty much a down payment on a new stadium. Especially considering you'd be guaranteed a Grey Cup early in the new stadium's life.
One thing that needs to be considered is building a stadium with good bones that can be easily upgraded. Commonwealth in Edmonton is huge but because of its size the cost to renovate it is the cost of a new stadium. In that sense it is a blessing CalgaryNEXT didn't happen. Updating a fieldhouse, running track, etc, etc would've cost a lot over its lifetime.