This just shows that, though they're not a headline of Mtv or something, the Beatles are still a hit and their songs still have meaning and good rhytm. That never changes.
And this kind of songs is for all ages. For example, my grandfather likes their songs and my 7-year-old sister likes their songs. (My grandpa's favorite is A Hard Day's Night and my sister's is Ob-La-Di, Ob-La-Da).
They've made so many songs with so many genres, going with psychdelia (Tomorrow Never Knows), some heavy rock (Helter Skelter), ballads (Yesterday), classic rock (Hard Day's Night) and funky pop (Ob-La-Di, Ob-La-Da). That way it's easier to please more ages, since each age has their personal favorite kind of song and these guys made them all with a blast!