When Uber came along it was a neato new technology and you can see how it "disrupted" existing taxi markets, many of which were poorly regulated and provided less than ideal service in their areas. Still it's quite amazing that people believed that there was any possible way to get the cost-per-mile down low enough - even with robotaxis (an Uber fantasy for awhile) - to make it live up to the growth/valuation hype.
Low margin business + an app does not equal EVERYONE GETS RICH but somehow...
Same with delivery services. No matter how much you can lower costs, there's still a limit to how much people are going to pay for it.
Also funny that we still call so many of these things "tech" companies.