If business owners, taxi owners, hotel owners and others who claim to be working for themselves need to depend on customers and customer satisfaction for profit, that is to be able to get money from them, are they really working for themselves?
Working for yourself mainly means that you are your own boss (No one is controlling you and your time). This doesn't translate to whether or not you are serving people for one product/service. And of course, you can't earn money if you don't deal with people (Individual, Government or company).
Maybe the people who are actually working for themselves are those who do not need people or to satisfy any customer to make profit, example like the traders who do not need to lure customers to their shop like business owners or hotel owners, or taxi owner that need to follow instructions from their clients etc.
You need people, you can't patronise yourself to build a successful business. That is why marketing is even thriving.