Because the USSCT is not a trier of facts, it is an Appealate Court. Procedurally, the USSCT would grant the Petition for a Writ of Certerrori, then oral arguments, then a decision to either overrule the lower appeals court decision OR allow it to stand.
IF the USSCT overules the lower court, they will then remand the Takings Case back to the COFC at which point a trial would begin.
I'm pretty sure that's how it works and that's why it just takes some time.
They do not rule on cases in the order in which they were accepted or agreed to be heard. That people have so much emphasis of the group that gave us 9-0 whuppin and a blue print for all other cases to follow is telling.