The alternative proposal would be that schools be held responsible for bullying. Simple as that. Only if looking away gets more costly and inconvenient than interfering a school will do it.
Right now, the best thing a school can do, from the school's point of view, is letting the bullies rule the school yard. It only has advantages for the school. Bullies are usually potential troublemakers. They are the kind of people who would get into trouble if the chance presents itself. Allowing bullies to beat up weaker kids gives the bullies and outlet for their aggression so they won't take it out on, say, school property or other property around school that might reflect badly on the school, and bullies honor that "silent agreement". After all, they get what they want, they get to beat up someone with impunity, so they don't have too much of a problem to play along the "rules".
That is a very favorable situation for the school because they don't have to deal with the bully problem. It does create a lot of really messed up kids, some of whom will spend a lot of time and money during their adult years in therapy to get over the trauma. Or it might end in a sad report about yet another kid who couldn't take it anymore taking a gun and revenge instead.