Or they'd get clever and try to encourage more hits by shaving down the pitcher's mound and shortening the field?
(That last bit, to create the question, "Howcome hardly anybody hits triples anymore?" "Because the distance to hit a triple would now go over the fence.")
@Cyber Liberty Depends on the ballpark. Some parks have deep enough power alleys to make triples possible, but it's not like the original Yankee Stadium with its
left-center field and center field depth. Babe Ruth could pick up triples there hitting the opposite way. (He would have had to hit the other way to pick
up triples, since he ran like a dump truck with a flat tire but the distances to those regions meant even he could pick up a few triples.) The down side
---it probably cost Joe DiMaggio enough home runs to keep him from hitting at least 400 in his career, that and DiMaggio's stubborn insistence that
the only "legitimate" hitting was pull hitting.
The Polo Grounds was even crazier. You needed to call a cab to reach its center field and left- and right-center field alleys:

Straightaway center field was 483 feet including a patch of it that ran under the elevated building that housed the home and visiting clubhouses and
the Giants' (and for two years the Mets') park offices. The bisected bleachers sat 463 feet from the plate. (
Now does anyone understand what
was so amazing about Willie Mays's catch in front of the bleachers, on the track, in Game One of the 1954 World Series?) The foul lines went 279 feet
to left and 258 feet to right.
Guess who played his first three Yankee seasons with the Polo Grounds as his home park? Babe Ruth. The Yankees played in the Polo Grounds as
tenants until John McGraw decided he was simply fed up with the arrangement and ordered the Yankees to find another place to play as soon as
possible---which they did, Yankee Stadium opening for the 1923 season. The Polo Grounds fitted Ruth's lefthanded power when the Yankees became
tenants there in 1920; the Yankees built Yankee Stadium to favour it. I'm convinced based on all available evidence that no matter what else you
might have read the real reason why Babe Ruth went from hitting 29 home runs in 1919 to 54 in 1920 is that he moved into a park (the Polo Grounds)
that was just too delicious for him---he didn't have to give a savage yank to pull balls to right field, and he didn't have to be intimidated by that
deep spread from left to right center. If he could hit 29 home runs with Fenway Park as his home park in 1919, it had to be cake for him to almost
double that number with the Polo Grounds as his home park.
But a funny thing happened to him on the way to Yankee Stadium: he hit 59 home runs in his second season with the Polo Grounds as his home park,
but fell back to 35 in his final year playing at home in the Polo Grounds. When the Yankees moved into Yankee Stadium, Ruth's home run totals for
his first four seasons in Yankee Stadium were: 41, 46, 25, 47. Except for 1927 (60) and 1928 (54), Ruth never again hit more than 49 home runs
in any season.
Suppose Ruth had gotten to play in the night ball era? I've seen several analyses of the prospect and it boils down to one thing: If he'd played in the
night ball era, Ruth would probably have finished with a slash line comparable to that of Willie Mays: .305 batting average; .384 on-base percentage;
.557 slugging percentage. He also might have hit about 600 home runs . . . but then, if you restore the two years Willie Mays lost to military service
in the early 1950s, Mays would probably have retired with 700+ home runs. Concurrently, if Ralph Kiner had gotten to play strictly in the day-ball-only
era, his own batting average might have spiked to something approximating Willie Mays's average . . . and he might have had a .400+ on-base
percentage. (Kiner's OBP when he retired was actually a little higher than Mays's: .398. And you can imagine how many more home runs he might
have hit than the 369 he did hit in a back injury-abbreviated ten-season career. Kiner's back probably kept him out of the 500 home run club, too.)