On our recent (April 2023 - British Isles Explorer) Viking Venus cruise no ABBA concert, no Beatles Concert. Instead, we had "Sounds of the Sixties," "Stage Door" - potpourri of Broadway and West End hits, "In-Concert-Duets," and "Southern Sounds," Johnny Cash, Shania Twain et. al. Nice to have a change.
By the way, the most popular program was an illusionist/"mind reader" Marc Paul. Truly mind-boggling act!