This is really about how to get upper-middle class wealth. The psychology of these millionaires is very different from the mentality of big startup founders -- sure, half run businesses, but these are lifestyle-type companies with no ability to scale.
Just because a business isn't suited for investment by VCs doesn't mean it's not a great investment for its owners nor that they necessarily possess lesser business ability or some kind of inferior mentality.
The people described here have a different mentality. They get rich by avoiding risks and cutting costs. It is a slow and systematic process with guaranteed results.
Startup people get rich by taking big risks and working hard to increase their top-line productivity and wealth-creation. It is relatively fast and chaotic process with unpredictable results.