Yep. A very good point. This is especially true in a sport like baseball, where there are only (I think) 11.7 scholarships available for a roster of at least 25-30 guys. You can split the money up in to a bunch of smaller pieces and academic scholarships can help, but at the end of the day it's a lot harder to get guy to walk-on or play for a very small scholarship at a $30,000-a-year private school versus a $10,000-a-year public school.
As a corollary, conferences tend to like institutions with similar academics because that helps keep the playing field "level" to a certain degree in terms of the types of student-athletes that are admitted into the schools. Of course, that's not to say that every school doesn't bend the academic requirements for admissions from time to time (e.g. Jeremy Pargo).