I think this is an acceptable use of the word. This particular account may not have turned a profit, but it might over time. And even if it doesn't this is certainly more revenue than you would receive with iTunes.
Setting aside the top earner on the service (because they're a record label), the second highest earner has earned $29 by buying $70 worth of songs. Third highest: $28 for $64. 4th highest: $24 for $66.
I have absolutely no doubt that with access to their database and a quick query you'd find out exactly what you find out in any MLM: the overwhelming majority of the people lose money. And I have a profound, abiding disrespect for something which is a business model when it is profitable and a consumption expense when it is not -- its not like Mary Kay recruits people with promises of access to wonderful new cosmetics.