How did the owner get 10 restaurants? They likely started with one and carefully scaled up over time as they could afford to, each time taking on risk that they fail and wind up with less than what they started despite all the effort. The business exists to benefit them, not to provide a place for people to work, that's a consequence. One reason employees make less than owners because there's less risk involved. They show up and do a job in exchange for money. Most employees have no equity in the business.
If you want to become a big shot owner making hundreds of thousands then you need to do it yourself and put your capital at risk, become a partner, or get a loan. There's no guarantee it will pay off but there's incentive to, which is why people do it. If there's no incentive or it's not great enough and the risk won't be taken. That means less people opening or expanding businesses, which leads to less opportunity for workers as there are less demand for their labor, and less wealth for society as there is less stuff to spend money on.
If you're not comfortable with the risk of being an entrepreneur and someone is willing to pay more for the same labor you're well within your rights to work for someone else.