Canada

Sounds reasonable if you think of the country as big. Attracting migrants is necessary as the birth rate in most educated countries is negative so the population, if left to itself, is declining. Migrants will mostly want to live in cities and probably the bigger ones with more opportunities. The infrastructure will mostly be needed to expand the big cities which will make them a lot less inviting. That might be less of an issue as everything electrified on the way to a low carbon economy, the smog will reduce as will some of the noise.