What about 1-on-1 interviews? Ask people the questions face-to-face, ask them to talk you through their answers. That's how advanced degrees like PhDs are assessed.
What we care about is that they can demonstrate they understand the problem and solution. The code is just the starting point for that conversation.
We have hired people who submitted failing solutions because they were able to think through the problem on the spot when we told them it failed and asked why.
Dijkstra exclusively gave oral final exams on a board. Allegedly, he stopped one of his former students after the first question and told him something to the effect of "you clearly know what you are doing by how you answered that, so you'll get an A, but your handwriting is atrocious." He spent the rest of the exam time making the student practice penmanship.
I'm unconvinced that oral exams provide the most secure and consistent form of assessment. I'm not even sure how to evaluate such a claim, though, so it may have to stand as an opinion.
I don't think there is an off-the-shelf product for cheaters, but it's only a question of time. Especially now that I mentioned it.
They probably failed even by the simple arithmetic that the time required to make a minimally good faith effort at applying a grading rubric is greater than the time a teaching assistant is paid to "assist" in the grading.
Your teaching assistants almost certainly scaled back their time grading your assignments to fit their allotted hours. If any of those intro classes fulfilled a writing credit you can probably start with available undergrad writing credit requirements, figure out how many hours your TA got paid, and look back at the number of students for a given TA to figure out just how much money you and/or your parents lost on the deal.
If you consider college tuition to be the money you pay to be educated, you're definitely right. Personally I think of college as something like a licensing or certification.
I learned twice as much at my part time programming job than I did in class (but classes where instrumental in getting me through technical interviews). But, once I had my degree I instantly had multiple 100k+/yr offers in a moderate COL area. For me, that is a good deal (but still a huge hassle).
And I can't do that without proper assessments!
If I think of class theater in an education that led me to 100k+/yr, that is a good deal.
If I think of class theater in a certification that led me to 100k+/yr, that is a good deal.
That it is a good deal doesn't change the the fact that class theater is a shady practice.
It's also detrimental. But since we don't have the tech to do speed runs against the versions of ourselves who took non-shady intro classes it can be easy to shrug.