They already were paid. The idea was that the college would take a chance and offer you 4 years of education and you would agree to that bargain and develop over 4 years. The benefit for the player is obvious- gain maturity, a college education, a chance in a lifetime opportunity to play before crowds and win games for the university you chose. This idea that money is everything in our choices is a really really bad one. I personally think that a kid going through 4 years of having to develop and stick with something is likely better statistically for the kids than making $100k a year at age 19 for being able to run and jump with no long term commitment to team or university.
Considering that 80% of adult pro athletes end up BROKE a couple of years after they retire tells me that the straight emphasis on getting paid during college might not be so great. Maturity, character and commitment > cash IMO.
Look, for the kids that want the cash and not the education, they should be free to go pro to the NBA G League, Europe or where ever. College was supposed to be amateur sports.