There’s some nuance that may not be getting communicated clearly. Unions do not “completely deprive a company of labor supply”. As has been stated elsewhere, they do not prevent a company from hiring non-union (or different union) workers. If they prevent workers from crossing a strike line, that would be anti-competitive and depriving a company of its labor supply. That happened in the past and it was wrong but there are laws against that for that very reason.
If there are only a handful of people who intimately understand Microsofts kernel, it’s not anti-competitive for them to band together to ask for higher salaries because they aren’t actively prohibiting MSFT from hiring someone else. Having leverage due to a constrained supply of labor is not the same as being anti-competitive and not illegal except in a few edge cases (like what we saw with the air traffic controllers in the 1980s, for example)
If there are only a handful of people who intimately understand Microsofts kernel, it’s not anti-competitive for them to band together to ask for higher salaries because they aren’t actively prohibiting MSFT from hiring someone else. Having leverage due to a constrained supply of labor is not the same as being anti-competitive and not illegal except in a few edge cases (like what we saw with the air traffic controllers in the 1980s, for example)