yeah, but the catch is the contract terms are finalized before the track is released....including royalties, unless of course circumstances change such as the label ceasing to exist and the rights being returned to the artist who can re-negotiate a better deal with someone else....
One problem with that, if it happens, is the track has already been released, so the market may already be saturated and mp3 file sharing networks flooded with it which would lead to leverage loss while nagotiating a new deal even if the track is a bona fide classic.
It makes no sense for a newbie to ask for tons of cash because he thinks his track is great and can't provide more intangible value (such as a known name) that will translate into sales...In most cases a label will give more money to an established artist than someone new and unknown even if a newbie sounds as good as the veteran.