This just seems like typical evolution of any sport, doesn't it? If nothing else, it just helps us remember our age.
Maybe (and it seems so to me) many fans just like "the game they grew up playing." But like any sport, baseball has evolved using metrics and specializations and strategies, just like it always has and the game you grew up with involved some bastardization that the previous generation was disgusted by.
I imagine the older fans watching MLB in the 1900's and 1910s probably got disgusted by watching 5 an rotations. "You didn't see ol' Hoss Radbourne waiting for his turn to pitch!" Or the use of specialized relief pitchers, and that whole new-fanged ERA stat. "If wins were good enough for Jack Chesbro, they're good enough for me!!"
Or fans in the 1920's who hated the whole webbed glove that you didn't share with the other team. Or in the 1930's, when they added foul poles and night games but removed spitballs. And I am not even going to get into the horrific fan reactions to the biggest changes in the 1940s. This was the absolute nadir of American Sports Fan Behavior. (And the 1950's gave us the slider and it's counterattack - switch-hitting.)
And some fans in the 1960's must have been completely aghast at the addition of the DH!! "Baseball is nine vs nine!!!" Or MLB expansion leading to 2 divisions in each league! And a whole new round of playoffs
And we won't even get into the 1980's and this whole specialized closer and the 1990's with dedicated set-up pitchers and dedicated LOOGY's.
Defensive shifts? Eh. Doesn't even register with me
And I will tell you now, I am just as shocked and appalled with the new "3 batter minimum", 7 inning double headers and runners on 2B in extra innings. But if I ever have a grandson who likes baseball, he will think of these as "the game he grew up with" and probably find some new rules or strategies or evolutionary tactics of the game that completely revile him. "Gotta tell you, Pops, I'm not a big fan of these new road games on the moon."