Are you claiming that having open-book tests makes it so that everyone can get an MSc? That’s what it sounds like you’re saying, so I assume that I just don’t know what you’re arguing.
Every system is going to catch some percentage of cheaters and wrongly punish some percentage of innocent people. The pandemic has put us in a bad position where we can’t use some of the more effective systems (in-class tests) for assessing knowledge / preventing cheating, so we are forced to come up with some kind of compromise, and in many subjects, open-book, take-home tests work very well (although they require more work from the professors).
The professors are overworked already. So that's one reason not to. Second, cheating is also fairly easy on open questions. Just get someone to prompt you the answers. That's what the proctoring software is for.
But it's the style of justification: because you can't catch them all, just ignore the problem. That's not ok. Education is supposed to teach you something else than cheating.
