Before we get to why many on-demand apps have struggled to achieve mass-market prices, it is important to remember why anyone ever thought they could: because Uber did it. The ride-hailing company that is valued by investors at more than $60 billion began as a luxury service. The magic of Uber was that it used its growth to keep cutting its prices and expand its service. Uber shifted from a convenient alternative to luxury cars to an alternative to taxis to, now, a credible alternative to owning a car.

Investors saw Uber’s success as a template for Ubers for everything. “The industry went through a period where we said, let’s look at any big service industry, stick ‘on-demand’ on it, and we’ve got an Uber,” said Hunter Walk, a venture capitalist at the firm Homebrew, which has invested in at least one on-demand company, the shipping service Shyp.

But Uber’s success was in many ways unique. For one thing, it was attacking a vulnerable market. In many cities, the taxi business was a customer-unfriendly protectionist racket that artificially inflated prices and cared little about customer service. The opportunity for Uber to become a regular part of people’s lives was huge. Many people take cars every day, so hook them once and you have repeat customers. Finally, cars are the second-most-expensive things people buy, and the most frequent thing we do with them is park. That monumental inefficiency left Uber ample room to extract a profit even after undercutting what we now pay for cars.

But how many other markets are there like that? Not many. Some services were used frequently by consumers, but weren’t that valuable — things related to food, for instance, offered low margins. Other businesses funded in low-frequency and low-value areas “were a trap,” Mr. Walk said.

Another problem was that funding distorted on-demand businesses. So many start-ups raised so much cash in 2014 and 2015 that they were freed from the pressure of having to make money on each of their orders. Now that investor appetite for on-demand companies has cooled, companies have been forced to return sanity to their business, sometimes by raising prices.

Look at grocery shopping. Last year the grocery-delivery start-up Instacart lowered prices because it thought it could extract extra revenue from supermarket chains, which were attracted to the new business Instacart was bringing in.