I suppose in terms of her dancing and stage presence, that was her peak, but I think the peak of her artistic expression really lies in both In the Zone and Blackout. In the Zone isn't personally one of my favourites but that's more down to my personal taste in that I prefer electronic music so Blackout to Britney Jean was bound to appeal more to me, but I can see why ITZ would have so much appeal.
I wouldn't say Glory was a flop. Britney Jean probably was, which I think is a shame as i love that album. But her contract with the residency prevented her from promoting it much. I think it was the promotional strategy rather than the material that was the problem. I like BJ more than Glory, I think that's because Glory lacks the club/dance tracks I like from Britney.
Not many people do in pop though, really. Especially as present culture is much more ageist than when say Madonna was around. I think Britney's had a good run though. I think her conservatorship stifles any passion she has for music.
Yeah, I can't think of any Beyonce tracks since Drunk in Love which were that big. But I'm not a fan, I don't follow her. Her Lion King album flopped though.
THIS. I feel like P!nk is so damn boring. She had so much life and energy in her early albums. It like she got scared of getting old and decided to conform to age norms just releasing bland ballads in order to stay relevant. Her material is so cringeworthy.