That's really the point in a nutshell - as much as it pains some to admit it, everybody here is simply a fan. Nobody here is a decision-maker (thankfully, at times), and having a better handle on the numbers - new or old - doesn't make them a superior fan. There are plenty of folks (myself included) that appreciate the info and additional insight that info provides when they aren't so over the top about it, because there's no doubt it's helpful, but acting like that info has "changed the game" is a little much. I would never argue that it's changed the approach to it at times as well as providing more focused ways to use the information, but the pitching rubber is still the same distance from the plate as it's always been, etc..
At the end of the day, a lot of the information has shown us (among other things) that...
1.) Defense IS important when valuing a player - which might be why teams have always deployed their best defenders up the middle to begin with (so even the "dinosaurs" understood that to a point).
2.) Guys who can hit AND defend without needing to hide them have often been undervalued - which isn't exactly an epiphany.
3.) "Great hitters" aren't necessarily so great when you position yourself better defensively - which wasn't exactly ever ignored to begin with. Those numbers have helped convince teams to utilize extreme shifts, but it's not like they didn't SHADE hitters a certain way when they saw established tendencies years ago.
4.) Pitchers (especially those without a third pitch or those who don't sequence things well) aren't likely to make it through a MLB lineup more than twice no matter how good their two best offerings are. This isn't exactly breaking news either, but the numbers have certainly helped teams focus more on having Catchers who can affect the game in more ways than with their bats.
The point is that no one here has access to any information those decision-makers don't. I have no problem at all with someone saying they disagree with a decision that's been made and using the numbers to explain why they would have acted differently. The problem is when they act like they've "uncovered" something earth-shattering because they read it on a public internet site and can replicate the numbers. Like I said, most of us don't need some chart to tell us guys like Acuna (and the like) are going to be special players, it's pretty obvious if you just watch him play.