> Are getting good marks that much more valuable than the actual education you would receive if you didn’t cheat?
The problem here is the incentive structure. The nature of grades is that some people will get As and some people will get Cs. If you get Cs, you might like to get As, but maybe you can't for some reason, from lack of intelligence to other time commitments to alcoholism.
Then your choice is to get a C on your own or maybe get a B+ by cheating. Given the same amount of learning, getting a better grade is better, so the only real incentive not to do it is the risk of getting caught. Some of the old methods for this were pretty unambiguous. If you submit the exact same essay as another student, or one that has been on the internet for ten years, what other explanation is there?
Rich kids would avoid this by paying someone else to do it for them. That has always been a problem. But now the cost of getting "someone else" to do it is approaching zero when the someone else is AI, so the problem spreads. But attempting to detect it with methods that have false positives is worthless.
On the other hand, testing students on their ability to do something that ChatGPT can do just as well? Maybe that's worthless too, because that's no longer a marketable skill when your future boss can get ChatGPT to do it too. So what they need to do is change the test to test for the thing the student is expected to be able to do better than the AI.