For reference, I know people who are professional entrepreneurs in the sense of doing it the other way around than you say, but they are not in a software/startup kind of business. They usually do things like open hot dog stands and similar easy fast food, open small bars, start a drywall business because even a non-professional manager can judge the quality of the work (horizontal? vertical? right angle? then it is OK) and search for similar ideas. I think it is partly about having skills like negotiation and organization so basically their profits can be interpreted as representing their more timid employees who don't have the cojones to argue down the prices of a vendor and then also demand a longer payment term, partly swimming in the small market gaps of large businesses, and partly about being bolder about tax avoidance than big businesses.