It's her fault she didn't just go ahead with a basic concert. She could still have showed she cared about her fans and made it special with a few deeper dives in to her repertoire and made it unique.
I'm guessing Adele saw the show Katy Perry did for her her Vegas residency and realised that she'd have to put in a bit more effort than standing in front of a piano chewing up all the miserable words in the dictionary and spitting them out with a few swear words as it's live.