[Mariner]

“Sacrifice bunts disappeared in all but a very limited set of circumstances involving a pitcher at the plate or a scenario late in a game where one run could end the game.”

They are routine in the National League, even today. It’s rare to see a NL game without a sac bunt.

[Alberta's Child]

That's because pitchers bat in the NL. This doesn't just force the strategy when the pitcher himself is at the plate, but because low-scoring games are more common you're more likely to see teams play for a single run even in the fifth or sixth inning.

Sacrifice bunts are actually counter-productive most of the time on a good offensive team. Moving a runner to second base on a bunt opens first base up and gives the defensive team a big incentive to intentionally walk a good hitter.