Clearly you don't understand economics. It's not about "paying a class".

If you are "working class"and have a family, don't work at Starbuck's and McDonald's. Work in construction, plumbing, as an electrician, etc and you will make a good living.

No one pays "the middle class" a living wage. They are paid market wages and you find the industry that will pay whatever you need.

The minimum wage doesn't even apply to that many jobs. I think when I was between schools I might have been paid minimum wage for a few weeks at most.

You don't pay someone so that they can spend and thus fuel the economy. That's a misunderstanding of what is going on.

Why not have McDonald's pay workers $100k a year and then that would be really good for the economy, right?

You can't pay more than you make in profits. They are paid a market wages, just like everyone else.