It’s certainly true that Uber’s lower price point expanded the market for private cars. In London, I rarely took taxis and now I travel regularly with Uber because it’s not that much more expensive than public transport.
However, this market growth isn’t quite what motivates the theory of disruption which is more about competitive response. Uber started at the top and competed head on with taxis and private cars. It lowered its standards and prices to grow their market. This is different from a company that addresses non-consumers with a product that doesn’t compete directly with existing players… until it does thereby disrupting them.
All this said, Clay admits Uber is a difficult one that doesn’t completely fit the model and the theory continues to evolve.