A few years ago a friend's son blossomed his senior year. His high school team was loaded. He didn't get on the mound until senior year. He absolutely dominated. All the local D1s expressed interest. One was an Ivy. The dad had attended the Ivy for undergrad and law school. He couldn't manage any pull. The kid was told he had to get accepted outside baseball. He didn't. He ended up pitching in the A10.
By senior year roster spots are typically filled. At an academically elite school the coach has probably used up his athletic passes with the admissions department.