I'll add another few items - but can only speak to Princeton (others chime in about other schools):
Until league play begins, every game, every year, is an audition/chance to earn more playing time. This is particularly true about the spring trip, where every player got multiple chances. Players who performed moved up the depth chart, others moved down. Every year the slate is wiped clean.
Because no athletic scholarships are available, EVERY player is essentially a recruited walk-on. The coach has no more sunk/invested in one player or another so PT decisions are truly based on what the coach sees in the present - not what he saw in the past and hopes to recapture.
Because no athletic or academic scholarships are available, a kid can leave the team ANYTIME AND remain in school. The players remain on the team because - for whatever reason - each wants to be on the team (regardless of playing time). The lack of attrition - much less transferring out - is a credit to the program (a player could be admitted, then simply decide not to play) and a coach who needs to be very, very sure of the player's desire to be on the team - regardless of that player's future college baseball success.
I personally think the pure baseball pressures are less on each player when compared to a P5 program; this allows a player to more fully experience a true college experience - but thru the lense of a D1 athlete. Academics, partying, drinking, girl friends, dining clubs (a version of social clubs), summer internships and more, can all be experienced to their fullest.
Players are assigned a first year roommate randomly from all incoming freshman (like in prison, as my son once put it). After that, players choose roommates; my son never roomed with another athlete.
(And, for the players not going to proball, the students will have their post-graduation jobs by the end of first semester senior year [apart from those going to grad school]. They spend the rest of their senior year writing a full year, bound, original research paper under the supervision of a full professor.)
Despite the best efforts to take fluff courses, the players do some serious learning. (I'm NOT saying all the profs are good instructors; I'm saying that the system is structured so that every student learns how to learn [not necessarily a pretty looking process initially]. So, my son took Astronomy (aka Rocks for Jocks) and coin collecting; surprise (!) they were legit courses. He did better in Econometrics (a math heavy course), than Astronomy.)