fans know how long it took for this album to come out. the references in this song were dated by the time the song was released. putting the two together makes me think she had this on deck at least a couple years.
as to whether beyonce was a better target, it's hard to figure. her music doesn't really move me personally, but i don't deny her vocal ability. i don't think the idea behind the song was just to throw rocks at whoever was the most popular at the time it was written; i'm sure her criteria were more specific than that. the bar is lowered now if it even still exists, but there was a time when people complained about ashanti's and britney's singing and their material.