What you didn't mention is that Uber and Doordash aren't very profitable. Also, it's in their interest to cut costs... which means paying their worker less.
So the charade is how do they stay afloat, and have this huge valuation.
The OP also specifically says the point of the charade is to "make huge amounts of money for the founder and the initial VCs". Uber/Doordash didn't just make huge amounts of money for the founders and initial VCs, it made huge amounts of money for early employees, later employees, current employees, the initial VCs, the later VCs. People have had years to exit their positions and unlimited liquidity to do so... some other rational actor was happy to buy the shares they were selling. If you say these companies are charades than so is every publicly traded company.
UBER currently trades at $27, well below its IPO price of $42 in May 2019, and we had pretty noticeable inflation in the meantime. So how have they made money for early investors and employees is not much of a charade: by selling to a greater fool :(