It's not "whatever they want", it's "whatever their employer wants to pay them", and if the employer doesn't have to pay them they won't.
Why do you think workers unions were created? Because workers did once work for "whatever they wanted", and their employers royally fucked them over and abused their labor and paid them shit.
And to address the point about if the minimum wage increases it'll "screw over the guy who worked his ass off to get that $2.00 incremental raise over the course of 3 and a half years", you would rather the guy barely scraping by not get a pay increase because you don't, you selfish fuck.
Unless they are a slave, they agreed to work for those wages, so its their fault if they are working for less.
I offer a man a job at a certain wage, and if this doesn't meet this mans needs he should have two options...
Tell me no.
Take the job, and look for more work on top of the work I offered to him if he wants more, quit me whenever he wants but Id like a 2 week notice out of courtesy.
Problem is, people think that just because you put your 35-40 hours in, that some how in some rule book that doesn't exist, that entitles them to enough income that they don't have to do shit the rest of the 16 hours each day that week that they are breathing, plus two whole days off as well. Certain things just aren't worth peoples time or money and 40 hours of it a week isn't gonna amount to any value to most, so why pay this person thousands for such things?
People who work harder are suckers.
Work smarter.