The root cause of the problem with the shift is that the players are not skilled enough to hit the ball where they want to. They can't bunt, they don't hit and run because that requires a skill. They can't defeat a shift which was originated for the big home run hitters to entice them not to pull the ball. Like a few above, I was the biggest baseball fan for many years...now I don't even watch the playoffs. Lack of skill, too many strikeouts and very, very boring.
It's all about the money ball analytics. Home runs and walks have been found to be much more important then stolen bases and spray hitters with .330 average like Boggs and Gwynn. Now you have guys like Schwarber who could probably easily be a .300 hitter with less power in another era. Instead he focuses on bulking up and the HR/walk or strike out approach. Thats what has been winning the last 20 years and that is what gets the big money.
Problem is that while HR's are fun to watch, the rest of it sucks to watch, mainly walks and strikeouts without much base running. If anything baseball was too slow to make rule changes to help he situation. The were probably hoping things would revert back as part of a cycle. It just was not going to, the stolen base being worthwhile myth was exposed over a decade ago. Teams weren't going to just start stealing again for the hell of it knowing that even in the 80's with the best Henderson, Coleman etc it was barely worth the effort. So much emphasis on a break even, sometimes losing play. Now MLB is bringing it back by making it worthwhile hopefully.
As far as the "skill" of being hit the ball anywhere. Some of the great hitters ever were dead pull hitters. Whose averages might have been 30-40 pts lower if facing todays shifts. Before more time, but take Ted Williams, considered one of the greatest hitters ever, dead pull hitter (I've read). They started shifting, and it hurt Williams , then he adjusted and had some success but never like before the shift. And that was a less "perfected " shift. Current shift conditions the last 20 years instead of Williams being a career .344 hitter , he probably is around .300.
Ryan Howard had a .258 career average, he plays in the 50's he is probably a .300 hitter. The shift is only part of the problem, the other part in the analytics, like the "heat" charts. Every pitcher, scout, manager has it at their fingertips exactly where to pitch a hitter. Howard had a couple real "cold" spots he couldn't get to. In the past there was much less exact info on those weaknesses.