Don't think this is true at all. Most important inventions were either communal/public endeavors or from the minds of rare eccentric genius.
Internet came from DARPANET which was a government and University joint venture - without DARPANET all the internet billionaires would have been impossible.
Most modern genetics and bio-tech would not be possible with the PCR discovered/invented by Kary Mullis - an eccentric scientist who at the time was just a wage earner at a company that ended up owning the patent.
Most important formulas from physics and math that lead to new technologies don't come from the wealth but again the random sprouting of eccentric genius that arises best with a dedicated infrastructure of public education and public access.
Buckminster Fuller made a number of innovations and inventions (not all were fully monetized because Fuller perhaps naively actually believed in humans and not corporate structures)
Nikola Tesla was famous for his electric inventions and he dominated Edison on the innovation front although Edison was a better corrupt businessman.
In fact, I think you would find far more of humanity's most important minds and innovators nowhere near the billionaire class. For every rare billionaire like Bill Joy who actually produced important innovations for the human race and was lucky enough to profit from it you get a dirty dozen like Donald Trump, John Paulson (scumbag leech predator investor who innovates zilch), Stan Kroenke (married into the Wal-Mart fortune and parlayed unique connections into unique real estate access while depressing communities all over), Donald Sterling (another slum lord), Jeff Skilling (Enron) , Angelo Mozilo (genuine PoS scumbag) and many more who are not innovators but simply good at playing the low level animal cunning predatory game of manipulating arcane rules based capitalism really well.
The real innovators of humanity come from the salt of the earth and then benefitting from infrastructure in place that allows anyone and everyone access to resources needed for achievement no matter whether they are from rich or poor. They also almost never are the ones profiting because the skill set needed to produce actual innovation is quite different from the predatory skill set needed to accumulate the most materialist tickets(money).
This list is not going to reveal the best minds of the human race that are actually advancing humanity. Its going top reveal a lot of shady, corrupt individuals who know how to manipulate both people and rule systems.