Why are foul balls strikes?

By 1903 both the American and National Leagues had settled on a foul ball counting as a strike, at least until there were two strikes. In some slow pitch softball leagues, a foul ball after two strikes is a strike out. Maybe MLB went to this rule to speed up the game. It didn't work. Consider two at bats. Babe Ruth swings and misses two pitches then fouls off the third. Ruth is still at bat. Ty Cobb fouls off two pitches, then misses the third. Cobb is out. How is that fair? It isn't. Get rid of this rule. A foul ball any time should not affect the count. It should not be a strike.