What happens if the inhabitants of the North stop breeding reindeer?

For the inhabitants of the Far North, reindeer are the main source of livelihood. After all, it is from the reindeer that the northerners get everything they need to live in these harsh conditions. The plagues in which they live are made of deer skins. Clothes and footwear as well. Reindeer milk and meat are their main food. Young antlers (antlers) are used to make medicines. Finally, the northerners move on reindeer sleds. Technology in such conditions can fail, deer cannot.

Therefore, the conclusion is unambiguous: the inhabitants of the Far North simply cannot survive without deer. And reindeer breeding is not just an old custom, but an absolute necessity.