It boils down to the boss will pay you an amount that it equal to or less than the value that you return to the company. Anything more, and he is losing money to keep you around.
If the value that you bring to the company is $10 an hour on average than he pays you $8.50 an hour and pockets the 1.50 as profit. (I know, there's overhead, taxes, insurance etc. but we're keeping it simple.) So while you the employee makes a profit of $8.50 the boss only makes a profit of $1.50 an hour and he or she has taken all the risks. I know one could argue he doesn't do any of that $10 an hour labor, but he or she has done a lot create the opportunity for you to work and as mentioned has taken all the risks.
When you demand to make $11 an hour for the same work the boss realizes that even after doing the work to create your job opportunity he is actually going to lose $1 an hour it quickly adds up. Why would the boss do this?
At the end of the day, it's a "for profit business" not a feel good charity.
I will add one further note. If you really believe that the value that you bring to your boss is worth more than he's paying then leave and go work for another boss that values your work more. In general there are no restriction to your seeking employment else where.
Let's also not forget that minimum wage jobs also have a higher turnover rate than non-minimum wage jobs and every time an employer has to hire a new employee, it takes at least 3 to 6 months or more (depending on the job) before that new employee is actually up to speed and able to provide service to meet or exceed what he is paid. Not forgetting the loss to the floor of the time that a manager or trainer employee must spend training that new hire. Every new hire is a net loss in profit for the time it takes them to become an efficient at their job. And if an employer experiences 50% turnover as many minimum wage jobs do (especially fast food), the business is experiencing significantly reduced productivity and a very low cost vs. benefit factor. Take the same workforce and increase the wage by 40% and you have a net loser for that segment of your workforce. Because we all know that even with the increased wage, that workforce today will not become any more stable. It will stay the same.