How many high draft-pick high-school players were committed to B1G schools, I wonder? How many in-state draftable players commit to B1G schools? There are certainly drafted players in B1G states who were committed to non-B1G schools.
If those big state schools can attract local players with financial need scholarships (i.e. as walk-ons) then I would guess that's what they're doing. But, it's a disadvantage not to be able to pile up top talent, if that's what is going on.