That people keep repeating this myth is evidence only of Musk’s abilities at self-promotion and the gullibility of the media to repeat a claim that sounds good without verification. Musk did not found either Paypal (nor did he found Tesla, but that is a separate issue). Paypal was formed by a merger of Confinity, which was a company which originally based on the PalmPilot platform for encrypted payments, with X.com, a company founded by Musk that was originally an online bank. After a restructuring (in which Musk was forced out because of his abrasiveness with other board members and resistance to many of the business strategies which made PayPal successful) the company reorganized as what is now known as PayPal and developed the essential tools for its implementation as an online payment system that used nothing that Musk worked on or that came from X.com.
Musk was a Series A funder of Tesla (well over a year after the company had been founded and was well into development on their first vehicle) and later litigated his way into being listed as a “founder” as well as dismissing the actual founders Mark Tarpenning and Martin Eberhard and driving the company toward various questionable business measures including extensive automation and trying to force OEM suppliers to offer Tesla steep discounts (both of which he had to walk back) as well as the 2016 acquisition of the failing SolarCity that is currently being litigated by Tesla stockholders. As far as SpaceX, it has indeed been successful and to listen to Musk it is all about his personal genius and innovation, even though the core propulsion technology has a direct heritage to the TRW Low Cost Pintle Engine (which didn’t stop Elon from trying to sue Northrop Grumman from ‘stealing’ SpaceX intellectual property), and every single time Musk opens his mouth and tries to talk about technical details it is evident to anyone knowledgeable about propulsion and space launch vehicles that he is imperfectly parroting phrases he has heard someone else use, often wildly out of context.
Musk has sold himself as a poor-boy-done-good and a victim of the forces of industry trying to push him and his companies down, but in fact he came from very comfortable wealth, enjoyed monetary support from both parents, has received enormous subsidies and tax credits from federal and state governments, and himself is the plaintiff in numerous SLAPP suits and whistleblower suppression in addition to his Twitter-raging and attempts at stock market manipulation. He’s a self-promotional narcissist who has demonstrated no concern for his employees safety or well-being, and despite the pretense that he’s doing this all for the sake of humanity he lives and spends quite lavishly upon himself, again while paying a lower portion of his income in taxes than one of his hourly assembly-line workers at Tesla.
Bezos, of course, has paid no taxes for many years, and Branson is well-known for shifting his wealth between tax havens to avoid paying any significant amount. It may be true that the combined wealth of these three billionaires would not abate the financial problems, but the reality is that they spend more money than most people make in their lifetimes on accountants and lawyers avoiding contributing anything at all while enjoying the fruits of public investment in research that led to the innovations they so publicly enjoy. I guess good on them for figuring out how to game the system (if that is your view of how things should work) but I personally don’t think getting wealthy by paying workers the minimum possible while pushing for ever-greater efficiencies while sucking at the public teat whenever money is to be had is something to be celebrated.