Same thing happened to friends of ours that visited last month. They are in their 40s. No kids. Hadn't been to the parks in 20 years. Thought it would be fun to see AK and HS since they've never been. I asked them if they had done their research and they had no idea what I was talking about. They were staying at our house, so not on Disney property. I advised them to be there before park opening, which they were> told them to go to FoP right away if they couldn't get ILL. They couldn't. I also told them not to buy
Genie+. Well, they got there, saw everyone heading toward FoP and decided to go in the opposite direction thinking that the crowds would die down for Avatar. A CM talked them into purchasing Genie+. Genie recommended that the best thing to do first would be the rapids ride (it was a cold day in January). They waited until it was open and discovered that there was no wait for that ride and no need to book it through Genie. By that time, all the other things were booked in Genie except for a Bug's Life which they went on next. Everest was closed. They waited in a huge line for KS. Afterwards, they were so fed up with the long lines, crowds and the uselessness of Genie+ that they left. They didn't even want to go to HS after that experience. They've sworn that they'll never go to Disney again given the price of the tickets and how little they got to see. They felt it was too crowded to even enjoy walking around and looking at animals.
I might add that my friends are smart people. They were aware that they needed reservations, as it said that on the website when they bought the tickets. However, nowhere on Disney's website does it indicate that if you want to eat at a sit down restaurant, you need to make a reservation 60 days in advance. Nor does it tell you that if you want to ride all of the rides in the park, there's little chance of that happening between the breakdowns and the crowds. Nor does it indicate that you should have a touring plan before coming in and understand the ThrillData data of which rides are going fastest on Genie+ and how to maximize your usage of Genie+. Why should it have occurred to them that they had to do more research on this? It wasn't like that the last time they visited 20 years ago.
Similarly, I haven't been to Six Flags in 20+ years. If I decided to go this summer, it wouldn't occur to me that I had to do anything more than purchase tickets (maybe express passes), check the crowd calendar and find out the opening and closing times. I assume you show up, get in line for the rides that you want and eat when you want. That's how most theme parks operate, even Universal Studios. People saying that people should do more research is odd when you think about how much research people do to go to Knott's Berry Farm or Cedar Point.