If I'm not mistaken, the Beatles were actually forced by their manager to change their whole appearance and some of their musical direction when they aimed to go mainstream. At one point they were playing in Germany at a club there and they used to light condoms (yep, they did that) and pin them to walls as part of their show. When they got the record deal, everyone had to wear the same clothes and have the same hair and behave better on stage (i.e. they had to bow after the performance). John Lennon dangled and shook his arms when bowing as a sign of protest, but it just came to be known as part of their signature style. But regardless of this, The Beatles eventually took a life of their own and gained better direction by themselves thanks in part to the initial prodding by their producers. But their music was never in question. And come on, they are The Beatles, that's good music even if they sported a Justin Beiber costume.
