With respect to deterring teaching I totally agree that we should go for it. There are ways to mitigate the value of cheating and ways to promote the value of learning, both of which are deterrents. Personally I like having lots of small tasks that build and follow on one another. If the student is working and trying to learn it makes sense and we get to reinforce the high level skills that matter. If the student is cheating it should become increasingly harder to keep a consistent story.
However if we turn this into a cop and robbers game that's what we're going to get.
As for the focus on GPA I think that the tide is turning. Employers need to find an alternative that doesn't eat their time.
And yes universities are rackets and aren't good value employers. They don't even offer job security anymore.