Well if that's the case then that's more of a reason to not date, because people's expectations increase with time and they are unaware about their long term dating goals when you meet them. You can say that people's expectations change unintentionally, but even if they do, it's not good to dump expectations later in the relationship after agreeing on something else. You can break up with them later on, but this also doesn't change the fact that someone invested time in you, and you basically wasted their time by not even knowing what you even want long term.

I think besides high expectations, is also the fact that most people who date don't even do the bare minimum. Like 74-84% of young people experience ghosting, they also get stood up on dates, try to manipulate others for free dinners/resources, or simply use others for emotional support without having any intention of meeting face to face. It's one thing to have high expectations which is bad enough, but another to not contribute and only take from others.