Your second and third suggestions will literally kill all research at anything but the most prestigious universities. It is elitism. Graduate students are not a

Your second and third suggestions will literally kill all research at anything but the most prestigious universities. It is elitism. Graduate students are not always RAs, they're usually not. They often teach, so you're not giving an accurate depiction of the incentives placed on them. Becoming a graduate student is not easy, the bar is not relatively low, and making it through the program is even harder. It's true that academic positions are not large enough but you're ignoring the private sector. Research scientists could not possibly be paid enough by universities. These would be graduate students minus the mentorship. A worse of all worlds.