I wonder how that would fare in our climate in finland, where the ground freezes and thaws all the time, breaking just about everything we lay in it, including roads, signs, pipes, foundations...

Rebuilding all houses will take perhaps a century. It might be easier and cheaper to add insulation to existing houses, such as using spray cork:

https://buyspraycork.com/

https://thermalcorksolutions.com/spray-cork-the-perfect-non-...