you do realize there's been a 10 second count to deliver a pitch for decades, right?
I'm aware. And I think it is 12 seconds in the majors. Every level of baseball has something similar. The difference is it's enforced more informally by the umpire and catcher. The idea of a clock counting down for everyone to see is just ridiculous. Besides, it's meant to be a pace of play thing, not a basketball like shot clock. If a pitcher is keeping good pace but once or twice needs to step off, no big deal. If it's a problem, I let the catcher know to get it fixed or we have a problem. Having umpired a lot of games (albeit not MLB), I have never had a problem with this. And I don't get the sense that pitchers have anything to gain from dragging either. Keeping the batter in the box and ready to go would do way more. Usually the pitcher is waiting on the batter to readjust everything on this body before every pitch. That needs to be done away with. All levels through college batters know except in very certain situations you better be set and ready to go. Start calling strikes every time Bryce steps out to redo all five pieces of protective gear he wears will shave time off games more than a pitch clock.
Besides all that, the biggest issue with game time is the push for high scoring games and home runs, etc. 2-1 games generally can be finished rather quickly (unless there are 22 pitching changes) compared to 8-5 games. We (umpires) are taught strikes and outs end games, walks and hits extend it. And I'm not talking absurdly huge strike zones, but for most of baseball's history the zone was much bigger, and pitchers were rewarded for hitting spots and "making pitches." See Greg Maddux in the 90s. Every game I've ever had the stick on where I had a consistent and pitcher friendly zone has been a pretty good game without a whole lot of arguments. Putting that (inaccurate) pitch box on television has fucked up the balance. Having to put the ball on a tee the whole game leads to alot more offense and alot more pitching changes (because pitch counts soar on more close pitches called balls and hits) which leads to really long games.
If you really want to fix things just get back to baseball. Bigger strike zones within reason. Going apeshit because a ball was 1 inch off the corner ruins the game. You'll also get starters going 7-8 again and reduce these tiresome pitch by committee bullpens.
Get rid of replay. I thought it was a dumb idea anyway. It has basically made football unwatchable and ruins baseball. MLB umpires are really good, and you don't need 12 different angles on a swipe tag that clearly beats the runner into second that looks good to the 45,000 people sitting there. Get your ass to the dug out and get a better jump next time. Will some calls be missed? Yup. But there are so few gross misses at that level it's just not worth it, especially if it makes the game boring.
A well-managed, well-played baseball game should (and does) move along at an enjoyable pace. Take all this BS out of the game and a lot of the problem goes away. To the extent that there really is a problem. Seems to me baseball is faring pretty well compared to professional sports in general, Little League and travel teams are booming, and the MLB has to be the most international and diverse sport in this country with huge potential to grow. And the MLB playoffs/World Series the past couple of years has been awesome. I don't care how long those games go as I've freed up my sports viewing time by not watching much basketball or football anymore.