I returned to college in 1989. While in grad school I had to teach, do odd jobs, be a gopher for my Prof and give tests.
The first time I gave one, I was shocked to see students cheating openly. Looking on other people’s paper etc. I warned them and they kept doing it. I finally had to threaten them.
They weren’t dumb btw, just cheaters.
What you describe is the broader context for the recent cheating scandal. I think cheating has been epidemic for maybe 50 years. I don’t mean everyone does it but a great number. Also, add in the fact that you can buy essays on the Internet. So millions of kids are really helpless at this point.
The school obviously is not trying to stop cheating. So students are very surprised when you complain. Don’t cheat? What a weird idea.