Harsh as the Yukon is, it is a walk in the park compared to anything in space, where there is no realistic possibility of a rush of individual prospectors.

Several areas of the ocean floor are covered with valuable polymetallic nodules [1] which are way more accessible than anything in space, yet this has not led to the equivalent of a gold rush.

[1] https://en.wikipedia.org/wiki/Manganese_nodule