That is, do you take issue with the fact that one person, employing many, profits much more than the people he employees or that he profits much more than his fellow man on the street?
The question of the self employed person making huge profits is another one. I advocate for a somewhat selfless mindset (beyond meeting basic needs for your well being and happiness). So if a single individual can make huge profits, that means it's costing the customers a lot of money. In my mind, a person making a lot of profit could save a lot of people money if they shared how they are solving these problems, and recruited others to help with the effort. So that might look like: make their project open source and help others join in the effort to make their solution more accessible. I see this as best for society.
What then of the food and shelter this entrepreneur requires? As long as food and shelter are hard to come by, the entrepreneur will be incentivized to withhold their solution from society and keep charging high prices to ensure they meet their own needs.
The solution I see is for society to provide for the needs of all. This can happen by ensuring that food and shelter are abundant. If we do that, we can see more developers and entrepreneurs willing to share what they know for the benefit of all. I believe that if executed well, this strategy can lead to a better and more innovative society than one in which every person is incentivized to withhold their knowledge from others.
Going back to your original question - it's not that I take issue with a single business owner earning a high profit, it's that I think we can do better. Instead of a few earning high profits while others freeze to death on the street, we can provide food and shelter to all, eliminate material poverty, and do this all while innovating faster. But to do so, we must drop the self-centered individualist mindset and think about how to both look after ourselves while also looking after others. We must think as a community instead of atomized individuals.
Simplest counter example is labor unions. There was in fact a huge campaign to dismantle labor union power in the United States. Look at the way labor power was limited by state force in the 1947 Taft Hartley Act for one example:
https://en.wikipedia.org/wiki/Taft%E2%80%93Hartley_Act
Meanwhile in Germany every big company legally must have representatives from the union on the board of directors. A lot has happened since Adam Smith and some of it was "masterminded" on both sides. For example the "organic" work day was 14 hours long until labor activists fought and in some cases died for the 8 hour work day. We have made many decisions about the structure of businesses in USA and unfortunately much of it favors the accumulation of power at the top to the detriment of most people.
Finally, we must recognize that no matter what structure we have, we can always imagine better ones. And we can apply the same effort and pressure to make change as has happened in the past.