So in 40-66 years Ireland decoupled its economy from the UK? That's a pretty long timeframe.

Also, the two countries have a very different mix of exports. Canada's primary export is probably energy (it's at least top 3). A small part of that is, say, exporting electricity to northern states (eg from Quebec). You can't really send that anywhere else. The rest of that sector is really crude oil. A relatively small amount is exported by port from Vancouver. The rest goes to US refineries via pipelines.

You're talking a decades-long project to send that elsewhere. And for what? Oil is a global commodity. You'd be selling it to someone else and the US would be buying from somewhere else. What have you really achieved?

Canada also produces raw materials and, in particular, lumber. Now this is important for the US construction sector, particularly building houses. So who are you going to sell that to? US and Canada use lumber because it's cheap. In a lot of other places they don't because it's not readily available or there are other factors that disfavor lumber construction.

Another sector is auto parts that go to Big Three auto makers in Michigan. Where's that going to? Particularly with China eating that sector alive. 99% of cars would be Chinese if it wasn't for trade barriers.

Well, I mean, realistically in 50 years oil exports presumably won’t really be a thing anyway. Canada is likely going to need to at least somewhat reorient away from resources.

Obviously decoupling from the US would take time. But the best time to start is now.