Excellent point. Although I think it would only had postponed the inevitable. DH players make money. So the union was in favor of it. In MLB, the union gets to call the shots.
The teams are all owned by corporations so they don't care.
The Millennials are not interested in the game. They just show up for the "atmosphere" of a modern ballpark.
Good point about interleague play, but the DH was a relic that should have ended years ago for one simple reason: As far as I know, the NL in Major League Baseball was the last league anywhere that still used it.