While the number of goods might be limited, the quality is not. If you have more disposable income, you are just as likely to spend it on a better car, a better house, a better laptop, a better phone, etc. Higher quality goods require more complicated manufacturing, more resources, more workers, and longer supply chains. All of which employ more people.

I'm not sure the quantity of goods is limited either. Looking at a supermarket today, the diversity of goods for so many niche purposes is incredible. And the internet has increased it an order of magnitude more.