Sorry, that's not realistic. Students commonly start studying the day before the exam. How will that work if you're cramming 4 yours into a single exam? It won't. It'll only lead to lowering the bar even more. Much more.
> The only people who actually care about your college grades are HR reading resumes for your first job, literally that’s it.
It's not about grades, it's about passing the requirements for a diploma. And the fact that only HR cares about it (in your rather corporate view of the labor market) is because everybody else assumes that the hurdle has been taken. They don't care about the diploma per se, just that you have a bunch of useful skills. Either HR tests you thoroughly (and they don't have a clue, so that's out of the question), or they rely on a system like the current one. Or do you think that a sociology degree qualifies you as a carpenter?
