I think most businesses fall into this so called middle class already. Perhaps this group could be labeled The Silent Majority of businesses given how these folks get up and do their work everyday without particularly expecting to escape the grind or becoming billionaires.

I see this in my extended family where almost everyone runs this kind of business and is so for several decades. They make much more money than if they worked for someone else, but none of them are going to break the $100M mark