Bruno Mars is currently selling about the same amount as Justin domestically. Justin is only ahead because of those first week sales powered by media hype and payola. Justin has done well for a comeback, but Bruno is really the male pop star of the moment now. Justin is just fulfilling his contract obligations.
And i don't see the need of having one well thought out era, when she can sell more with two albums with 1\3 the effort.
Nothing, from a commercial standpoint. Aside from the fact that they pay millions to produce all of her songs and she ends up pulling in less money annually than Gaga anyway.
