It's possible tastes have changed, but historically it's been pretty popular in the US. I think the games going much slower and longer and the change of the game to be more about power hitting and strikeouts at the expensive of balls in play has made it worse even for the people who might otherwise still be interested.
Pitching changes lead to a commercial break - and current coaching strategies lead to frequent changes. Combine that with everyone consistently swinging for the fences vs. putting the ball in play with runners aboard, and the game gets tedious to watch.
Baseball had a first mover advantage which helped them a lot. Playing just about every day also helped create a routine for people. But as new generations come people are realizing that baseball has the least to offer among the big 4 sports in the US.
Baseball is one of the worst sports for television because the game is done when the game is done. That just doesn't work so well for the half-hour time slots that TV uses. All these dumb rule changes lately to try to get the games to always take no more than 3 hours is MLB trying to fit the TV model.
In-person and streaming don't have this constraint. That's what MLB should be emphasizing. So this is a great move. We need baseball to be an in-person/streaming-first, tv-last game. Then just say "we're not like the others, how about enjoying baseball and your other favorite sport?"
