When Jack reveals that he didn't write all of the songs, he credits four people (John, Paul, George, Ringo). The crowd cheers as he gives away the music for free, but because people do not know what happened during the global blackout, they should think that the four song writers should receive all of the credit and royalties associated with the recordings.
It’s not as if the people never existed, only the band, and the logical conclusion of all this speculation is exactly where the movie takes itself. I don’t want to spoil the party, but it feels like exploitation.
Neither a no-nonsense delight like She Loves You nor the White Album-style head trip its premise might suggest, it's more of a Yellow Submarine sort of film: crowd-pleasing and sometimes enjoyable, but pretty damned dumb when you stop to think about it.