This comment confuses me. Are you saying that Europe... destroyed all their mountains? Or what?
There are a lot of people that live in Europe, it's not that there was so much wilderness and now it's all paved over. Australia and Canada have huge areas of wilderness because it's partially uninhabitable. Not many places have that.
Wilderness is not just the mountains. It is the complete ecosystem, the most productive part of which is not rock and ice (which remained largely untouched in Europe as in North America because as you note there's not anything you can really build there) but the meadows, valleys and forests most of which are indeed paved over in Europe. How many primitive (i.e. never cut and regrown) forests exist in western Europe? How many subalpine valleys in the Alps have no village or pastures in them?
Don't get me wrong, there are many beautiful places in Europe. I've had the pleasure of doing several long distance walks in the Alps, the Pyrenees and in Corsica. But it's not wilderness.
Even uninhabitable places need protection from resource extraction if they are to remain wilderness. This is how Canada lost most of its coastal rainforest. Not because there are cities there now, but because it was all cut down and sold to make shingles and 2x4s.
There are a lot of people that live in Europe, it's not that there was so much wilderness and now it's all paved over. Australia and Canada have huge areas of wilderness because it's partially uninhabitable. Not many places have that.