I can share my son's thoughts on why he didn't play summer baseball. His coaches were fine with it, and they knew when he was recruited where his priorities were. Nobody was surprised.
1) Money. He selected a private school. The bank of Mom & Dad agreed to assist with 50% finances. He was responsible for the difference plus living expenses. He needed the money which leads us to 2) below.
2) Internship. He had a summer engineering internship ($$) that eventually led to an engineering job offer as a rising senior. The internships were invaluable to what he wanted to do professionally.
3) Innings. He felt he pitched enough innings during the regular season, and more innings on the mound were just going to wear him down.
My son loved college baseball, but he had no aspirations of playing baseball beyond college. We looked at college summer baseball as an internship but it just wasn't providing the experiences that he wanted to continue his engineering path. If anybody wants to be a professional baseball player, then playing summer college baseball is almost a got to have if healthy.
JMO.