you missed the last chunk of that sentence: " that the user decides it is not worth the effort to investigate alternatives.". If I don't have a Lyft account and have only ever used Uber, I may not want to go through the hassle of downloading the app, registering, having Lyft text me, etc etc.
It's still not price gouging. Your premise is that the price difference is not low enough to bother checking, which means there is no price gouging.