When the rumour was $3.2bn he wasn't going to become a billionaire despite his video stating his was - so now the price has dropped he certainly isn't one.
Also - what does Beats have to do with his career in hip hop? Hip hop didn't make him almost $1bn, an electronics company he co-founded did. It just irks me every time I see 'hip hops first billionaire'. It has absolutely nothing to do with hip hop.