They can bring a lot of jobs and experience and also generate a lot of taxes for that country, if they can relocate to another country.
Don't believe in fairy tales.
These entities value their profit margins more than the coin they mine or the country they operate in. They'll pretend to create jobs and whatnot, but the reality is very different, and we have seen that already in countries such as Canada and certain states within the US. Miners were allowed to settle there in return for job creation, but nothing of this actually happened.
The fact that we still talk about Bitmain shows that a lot needs to happen for it to be overtaken. They are losing dominance in the crypto space, but it's quite a slow process. I would have expected legacy entities to be more aggressive, but it seems that they still consider this space to be too much of a risky bet rather than a profitable opportunity.