Perhaps the colleges could do it indirectly. I can see the problems with a particular school giving equipment, as it could be seen as an attempt to entice recruits to come to your school. But perhaps an organization could be set up where colleges donate their equipment, and the organization distributes it. That way, there's no enticement.
What happens with used equipment anyway? I have to imagine that there's a lot of equipment, especially at the bigger schools that may be too old for them to use that might still be up to specs for a high school to use. When I played in high school, we had new helmets that had packets of foam and water. They were pretty cool (this was around 1981). I didn't get one. I had an ancient helmet that was too small and had canvas webbing for padding in the top.