Combination of things
You can talk about the run ending and whatever, but if it was good music then it doesn't matter.
The album was not a proper album. Any real fan knows that Lloyd Banks second album was 'The Big Withdraw' but because of Banks' stupidity, he had that leaked. Even though it is not mastered or complete (missing singles), that album to me is one of the best albums from the 2000's. People complained sometimes G-Unit was too mainstream, but that was traditional grimey NY hip hop that Banks made, and 50 let him make to release.
So yeah, the album flopped because it wasn't a good album and it wasn't the real album. It was a rushed album that was made so quickly because Banks lost all the original material.