Reverse example. Vue cinemas halved their ticket prices pre covid. My local one appeared to get much more than twice as many customers and of course they benefited from additional concession sales.Prices don't automatically have to rise, though. If you increase passenger numbers, then revenue increases without price rises. In fact, depending upon elasticity of demand, you could increase revenue by reducing prices if passenger numbers increase high enough.
It's like our local council's car parks. They put up prices and a year later discovered total revenue fell because people didn't use them. Instead of reducing prices, they put prices up again, and even fewer people used them, so total revenue fell for the second year running.
Cheap day returns at 10p more than a single was a similar idea. It was basically introduced as a promotion: return off peak for the same price as a single. The network card was also an exercise in reducing fares in exchange for increased volume so these are hardly new ideas even on the railway.