Baseball doesn't limit bat construction. It only stipulates that bats be made out of wood, for good reason. Because baseball is essentially a battle between pitcher and batter. A pitcher has only his arm, which can't be improved by technology, that's why a MLB bat can only be made out of wood (or else, the pitcher's life might be endangered). But because of modern manufacturing technology, a modern bat is quite different from one of, say 50 years ago. It's much lighter, because the handle can be made thinner, so that the hitter can generate more bat speed.
The comparison with tennis is not apt, where both competitors have their choice of any racquet and string technology. If both have choices, then why limit them?
Golf is another interesting example. There the competition is between the golfer with his modern clubs versus the golf course. And the most famous courses date back generations (OC St Andrews from the 15th century). Around the time Tiger Woods took over the game, he was hitting prodigious lengths off the tee, there were howls advocating regulations to limit driving distances, in the name of protecting the integrity of the old venerable courses. Do you know what was wrong with that from the business point of view?
Golf manufacturers make fabulous money from selling ever newer clubs to the playing public. How can they justify that if the pros cannot use the latest technology? As far as I know, the golfing authorities (USGA and R&A) have never limited technology on golf clubs; all the club regulations are on the lengths of the clubs. And a good thing that they didn't, because it turned out to be unnecessary.
As it turned out, the tournament organizers had a few tricks up their sleeves. One, they keep making these courses ever longer; that's why these clubs keep buying land, to expand these courses. Two, they make the fairways narrower and the rough rougher. Turned out these beloved courses couldn't be made obsolete by the newest club technology. 20 years ago, Tiger astonished by driving 300 yards; now if a player can only drive that far, he's not competitive.