Because it is a huge financial benefit, but the individuals still have skin in the game. Even though the tuition is low and the scholarship makes it lower, those individuals still pay enough that they value it and work hard and most take advantage.

My parents were involved with a perpetual-education fund-LIKE organization for a while, and the results were not good. Part of the problem was that the individuals didn't have any skin in the game, they were given full scholarships plus assistance. As you can expect, many dropped out or flunked out and even one or two had honor code problems that led to them being kicked out. One or two got bad grades (I believe the scholarship required that you maintain a "B" average which isn't that hard at BYU), and then went back and said "I promise i'll get my grades up, give me one more chance, bla bla bla" and since the organization was small enough they gave them more chances and it didn't work out. One person who was kicked out of BYU for honor code violations asked if they could attend UVU instead which was more expensive and not the point of the scholarship. I believe they helped 20 people and maybe 2 were success stories.

My learnings are that individuals need "skin in the game" and you need an impartial person who is not connected to the recipients to be the arbiter and that person hasn't be cold and lack empathy.