That is one of the good things about football. You have to lift year round and you have to go to summer training, but it is probably the last sport where you can do really what is required by the school team only and still have a good shot at playing.That's because you just can't play unless you are 200% committed to the sport and nothing else. You can't just "be on the team" and play some JV and maybe get in for some scrub time. Lots of times kids get told "if you aren't on the year round travel team, then you're not serious and you won't play". Or similar. So kids just give it up.
Not just baseball, its most hs sports now, particularly at bigger schools. Gone of the days of kids just playing for fun.
Pretty tough at a large school playing basketball or baseball if you aren't doing the travel stuff but it's possible. I really don't think our HS baseball coaches push it. We've had a couple good players the last couple years that didn't do travel baseball in HS. Most do, but I don't think they pressure kids to do it. My kid does it because he would practice and play 365 days a year if he could. But I think it's a lot more about putting in time on your own however you can throughout the year vs. doing travel ball.
If coaches are using that as some virtue signal and making it a prerequisite to play, that's a real shame. Being realistic and understanding kids that do that kind of stuff might be better is one thing. Making it seem like a prerequisite to even get a fair shake is not OK, especially at the expense of other school activities. I'm sure it's common unfortunately.