Only at the top of the fourth inning and two hours in to Cubs/Brewers game. Why so slow? Bad pitching and fielding, which is why any rule change MLB may make to require relief pitchers to face at least 3 batters is idiotic. You don’t want rules that keeps bad pitching in games, they will go on and on.
Nothing, not mound visits, and not replacing pitchers makes games go longer than continual walks and hits.