And some of the best players of all time sat around and did f*** all during the offseason. They didn't work out at all (see Kruk, John). But at some point, players realized that if they worked out during the offseason, they could get better than their peers and now that's the norm. Players don't show up to camp 20 lbs overweight and use Spring Training to lose a few lbs. Why do you think we now have stables of pitchers who can throw 95+?
Times change and I believe these labs are currently what is producing the very best results for the average player. Sure there are still naturally gifted players who can f*** around on the sandlot and be stars, but if you took 100 player and put them in the sandlot and then took the same 100 players and put them in the lab - I surely expect the lab will produce more great baseball players. Accordingly, I think we'll continue to see more and more players gravitate to these labs to fine tune and improve their games. The players that don't will eventually fall behind and will be replaced by those who are. There's too much money in baseball for people to not take advantage of the resources that are producing the best results. I mean we have players saying they only want to be drafted by the Jays because of these facilities...
Do you play golf? Remember when 'lessons' used to be from the pro on the driving range? Sure they produced some results, for some. These days the best way to improve your game is to get into a facility that videos and analyses your swing. It shows you spin rates, axes, contact point, etc. Lessons in that environment are producing SIGNFICANTLY better results and the pro who's telling you to keep you head down on the range. You can see the video and track the results in real time. It's no different in a baseball lab.
I understand the need for rest - they can go do that for a few months for sure - but I certainly see more and more labs being created and players routinely using them to train in the offseason. Adapt or die Grady.