A lot of schools are fine with kids going on missions. Stanford seems to be excelling with RM types. One of their team captains is an RM.
I don't see it as a black and white issue. I think missions help some and hurt others.
I think the reason we don't see missionaries at other schools as much is not because those schools don't recruit them, but because those kids typically go to byu or Utah no matter what (with some exceptions)