unions

Even if you don't need a second job, your boss is exploiting you

If you need a second job, both of your bosses are exploiting you.

If you need a second job, your boss in your first job is exploiting you.

That doesn't logically follow at all. It's very possible to be paid 100% of the value your job creates (in other words, you create zero profit for the employer), while that amount still not being enough to sustain you. That depends on the job.

That said, I think it's the government's job to make up that difference itself if/when it exists.