I've read a lot of old threads on this site. People always did ask questions about D3 schools, but 10-20 years ago the answers to those questions were not very helpful at all. Now there is a pretty good representation of posters from all levels, so that questions about P5 and the draft get experienced answers, and so do questions about D3 and juco. That is a good thing, since where a person thinks their son is going might not, in fact, be where he ends up.
For coaches, I think there's a difference between a team that consistently goes .050, and a team that is closer to .400. With the former, the school might wonder why they are paying for that sport at all, and it would be hard to recruit in order to improve. But being below .500 still offers the chance of having a standout year or some signature wins, and if the coach is graduating good people, then why not keep him? I would imagine that in many cases it would also depend on what the alumni want, and at most schools, the only alumni who care about the baseball team are going to be former players.