After a recent rash of tour cancellations in the wake of weak ticket sales, concert industry observers were predicting the next shoe would drop for the Pussycat Dolls ‘ poor-selling reunion tour, and that high heel hit the floor Monday afternoon. The group announced that its U.S. outing was being called off “after taking an honest look at the North American run,” while shows in other parts of the world will proceed as planned. Although the Dolls did not specifically cite ticket sales as the reason for bowing out of the dates, there were no other excuses offered — in contrast to other recent cancellations where alternate explanations have been given for pulling the plug on arena or stadium tours, with some rationales more credible than others. “Dolls: We want to share an important update with you,” the group’s social media message began. “When we announced the PCD Forever Tour, we hoped to bring the show to fans across the world.…