Because you can't offshore your clogged toilet or broken HVAC issue to someone abroad for cheap on a whim like you can with certain cases in tech.

You're dependent on a trained and licensed local showing up at your door, which gives him actual bargaining power, since he's only competing with the other locals to fix your issue and not with the entire planet in a race to the bottom.

Unionization only works in favor of the workers in the cases when labor needs to be done on-site (since the government enforces the rules of unions) and can't be easily moved over the internet to another jurisdiction where unions aren't a thing. See the US VFX industry as a brutal example.

There are articles discussing how LA risks becoming the next Detroit with many of the successful blockbusters of 2025 being produced abroad now due to the obscene costs of production in California caused mostly by the unions there. Like 350 $ per hour for a guy to push a button on a smoke machine, because only a union man is allowed to do it. Or that it costs more to move across a Cali studio parking lot than to film a scene in the UK. Letting unions bleed companies dry is only gonna result them moving all jobs that can be moved abroad.