I wouldn't worry about who knows more. Sounds like you both have some knowledge about how it works. I would focus on helping him fill in some gaps in his thinking, not disputing it.
The process changes for any individual from month to month. His current strategy is probably appropriate for him right now. A showcase probably isn't going to get him recruited right now.
I would ask him to educate you about his current plan (not to defend it). If it relies on tournaments, team showcases and the travel coach, is he ok with limiting his college choices to the schools involved in those activities. He may be perfectly happy with that approach right now. If not, you can help him figure out how and when to approach other schools that he's interested in.
You don't need to talk to him about it right now, but if his plan isn't working for him in a year or two, then he can update his strategy. At that point he'll probably want to start contacting schools directly. That's when measurables from a showcase will be helpful. In the case of a catcher, that's EV and positional velo (IMO).
One thing that I would make sure that he understands... even in his "if you’re good enough" scenario, most coaches are looking for kids who really want to be there. So, it's not just a matter of being good enough.