History, especially the industrial age, says that attitude leads to a race to the bottom. There's always someone who's willing to work for a little less, in a little shittier conditions, to pack a few more family members into a shitty apartment to make do.
If you leave it up to each worker to fend for himself with no negotiating power beyond his personal freedom to walk out, you get sweatshops and poorhouses in any industry where labor is fungible. If you want nice societies where average people can live in good homes with yards and nearby playgrounds and go to work at jobs that don't destroy their bodies and souls, then something has to keep wages at a level to support all that.
I'm not necessarily a fan of unions; I think in many cases you end up with the union screwing you from one side while the corporation screws you from the other. And the public sector unions we have today team up with the state to screw everyone else. But workers at least need the freedom to organize, or all the pressure on wages and conditions will be downward for any job that most people can do. The alternative is to have government try to keep wages and conditions up, and it's not good at that, so it just creates inflation with wages trailing behind.
