Why baseball games are long

The umpires don't enforce Rule 8.04:

When the bases are unoccupied, the pitcher shall deliver the ball to the batter within 20 seconds after he receives the ball. Each time the pitcher delays the game by violating this rule, the umpire shall call "Ball." The intent of this rule is to avoid unnecessary delays. The umpire shall insist that the catcher return the ball promptly to the pitcher, and that the pitcher take his position on the rubber promptly. Obvious delay by the pitcher should instantly be penalized by the umpire.

Or Rule 6.02:

6.02
(a) The batter shall take his position in the batter's box promptly when it is his time at bat. (b) The batter shall not leave his position in the batter's box after the pitcher comes to Set Position, or starts his windup. PENALTY: If the pitcher pitches, the umpire shall call "Ball" or "Strike," as the case may be. The batter leaves the batter's box at the risk of having a strike delivered and called, unless he requests the umpire to call "Time." The batter is not at liberty to step in and out of the batter's box at will. Once a batter has taken his position in the batter's box, he shall not be permitted to step out of the batter's box in order to use the resin or the pine tar rag, unless there is a delay in the game action or, in the judgment of the umpires, weather conditions warrant an exception. Umpires will not call "Time" at the request of the batter or any member of his team once the pitcher has started his windup or has come to a set position even though the batter claims "dust in his eyes," "steamed glasses," "didn't get the sign" or for any other cause. Umpires may grant a hitter's request for "Time" once he is in the batter's box, but the umpire should eliminate hitters walking out of the batter's box without reason...

Of course, if umpires started calling balls when pitchers didn't deliver a pitch within 20 secons, or balls and strikes every time batters stepped out of the box "at will," civil disorder might ensue. Personally, I don't care that Major League Baseball games tend to last a long time. It's the nature of the sport, part of the charm, as Tom Kirkendall at Houston's Clear Thinkers might (or might not) say.

The Yankees play the Red Sox tonight. Astros play the Cardinals Tuesday.
[official rules of baseball]