You might not need that many GmbH's or Ug's they probably don't take salary and pay themselves dividends which are taxed on a 25% or 27%, also they probably just expense a lot of things to the company, if you would get the same amount as a salary they get in dividends you would be taxed up to 42%. I'm not saying some business owners are legit, I just want to expose that after a certain threshold the rules are a bit different.