I think it's especially difficult for Taylor. For example, Katy Perry's Witness, an underperformer by any standard of analysis, peaked at number four on the SNEP Albums Charts. Taylor's most successful album peaked at no. 9 there. Fortunately she makes up for her severe underperformance in Europe by doing fantastic in Asia. All of her lead singles (except Cardigan) in Japan have debuted within the top ten, and she has 7 top ten hits there. For comparision, Rihanna (who's European dominance crushes Taylor) has had her biggest hit there peak at no. 42.