There are those who owe their entire careers to Dr Luke and Max Martin (Britney, Katy, Ke$ha).
There are those who began using them to keep relevant (P!nk, Avril, Kelly )...to varrying results.
Others even switched genre, abandoning country twang for whooshing dubstep (Taylor) or rap verses for a chance to do their dance (Nicki) . Some futuristic artists traveled back to the present for their beats (Xtina) and not even those who claimed they didn't want their songs to sound like Katy and Ke$ha (Rihanna) could resist.
Will Lady Gaga and Beyonce be able to carry on without Luke & Max? Who will use them first? Or will neither?