Any professional level athlete is going to be exceptional....either with easy measurables like height, speed, 40 times, or with an elite skill level....probably both. Looking at kids that play sports it will run the gambit from kids that stand out to kids that are having a good day to not tip over standing still.
There is a reason it is rare for a person to be a multi sport athlete after high school. Raw athletic ability is not enough. Time commitment and ability to play and understand a game at a higher level in multiple sports just does not happen that often. Pointing to world class athletes that have done this or very rare outliers really are the exceptions that prove the rule.
As for the rich vs non rich schools, yeah, money matters.
For example 4 schools where I live: School 1 is a private school, expensive to attend.
They have facilities that are gorgeous, nicer than many D2 colleges. Their baseball coach is just a full time coach, not a teacher. They have trainers and a physical therapist that work with the team and a staff of about 5 or 6 guys.
School 2 is a successful public school. In the running the the regional title every single year. Their coach is a teacher but has been the coach for over 20 years and is connected in the baseball community bringing in well respected guys to work with his players. They have a full indoor baseball/softball building with cages, weights and mounds to work in the offseason and winter.
School 3 (my sons high school) is a public school, a new school but probably serving an area considered lower middle class by most. They have a revolving door at coach. One teacher for a couple of years then another. Not much experience as these guys were basically high school players who happen to teach there. Outdoor cages, no indoor facilities at all.
School 4 is the public school in the "bad" part of town. Literally dads coaching and no facilities. The field looks like a Babe Ruth public field with a temporary fence that blows over on windy days.
So, money helps with better facilities, better coaching and the status that comes with winning. The amount of kids that try out for these teams goes hand in hand with the amount of winning and the facilities. At the School 4, who did not win a game last year, there is no status related to playing baseball. At school 1 and school 2 where kids regularly move on to college, there is. So it goes I guess.