Back in the 2000's, Analytics started to become prominent in the game of baseball and has grown to the point where every single team has a department solely devoted to analysis.
While the use of analytics was in it's infancy there were people saying "baseball has been around since the 1880's" and it is comments like these that delay the arrival of almost every new thing in life because it take real courage to implement something new in the face of these type of comments from people with power and people without power a like.
Baseball didn't snap it's fingers and change into full saber metric mode overnight. There was a guy who was working on it in the 50's and didn't real understand the implications. Bill James started publishing in the 70's and was mostly ignored by baseball until a team has success with it. Then once you see a team have success with it... it kind of trickles across the landscape for years (even decades) followed by a flood and then a trickle of the last remaining stragglers. The Twins were in the last remaining straggler group BTW.
The opener idea was just introduced... there will be a trickle and until then... those trying to implement are going to have to endure the "Baseball has been around since the 1880's" comments just like... always.
Not to be condescending or anything.... analytics have not improved the game one bit. It has given baseball nerds stuff to argue about, mainly. And just because something is a new fad, doesn't mean it is a good idea. Think bell bottom jeans.
You still have to field a team of guys who can throw, hit and field. And analysis means nothing in that blink of an eye when you have to hit a 97 mph four seamer.
Analysis tells you that the shift is employed a lot. But an intelligent analysis will also tell you that you can beat the shift every time by hitting it the other way, dropping a bunt etc. But if you do stats against a stubborn cuss that won't adapt (Think Ted Williams... but he was a special case) the success of the shift gets exaggerated. Against a bunch of guys who know how to handle a bat, the shift should fail more than it succeeds. So analytics that tell you to employ the shift should change back once guys consistently try to beat it.
I have used the opener idea. I think I won two championship games (middle school) doing it. But it was a playoff game and there is no tomorrow. Fresh arms can go 3 innings easy. I see it wearing down over a long season.
I also think it slaps your starters in the face and will end the incentive contract. Openers will never get a win. Bummer man. The guy who comes in after the first three innings can get the win, even if the opener did as much to earn the win.
Being old school don't make you wrong.