Of course, we do agree on one thing. Performance over time is not nor ever will be an outdated concept. What is outdated IMO is some notion of 500 at bats being the line where by you have enough intel to make the decision.
I'll still ask you how you do that assessment and you'll continue to tell me you don't know and it doesn't matter. Performance over time literally has to happen over time. You don't get ABs without Games, you play one Game per day. SSS in Baseball is about the most misleading of everything we look at. You get out of SSS by more sample size. I don't know how you get that performance against advanced competition without performing against advanced competition.
If you could do it in a world without consequences, whatever, that's not the rules, context or world of MLB.
AFWIF its not some hypothesis. There are loads of players under 20 playing in the top soccer leagues all over the world. That is a fact. Its proven that young players can play at the highest levels. That is a fact.
If you want to discount that because of some notion that baseball is harder and takes more development so be it.
My answer is different to this. It applies to all of these clowns that want to talk about pitching mechanics.
GMing in MLB is typically a shorter gig. If there was any merit to rushing 20 year olds into the Majors to win, you'd see a bunch of Teams doing it because most GMs don't even last the Service of a ML Player..
Also, if streaming 20 year olds into the lineup was a thing, you get new 20 year olds every year. What happens when they turn 21 or 26 or 28 or 31.....do you have to get rid of them because they aren't 20 and only "20" wins? So that's kind of dumb right? You tell me you want to be more selective than just streaming 20 year olds onto the roster and I'll again ask how you make that decision....which is a question you don't want to answer.
If we want to answer the question of Soccer vs Baseball, we probably can with things like peak skill/talent levels, exposure to quality competition and the relevance of experience, but let's just look at how many Teams commit to what you want to do in a world where only results matter.