That's not how the draft works. If Carson Beck is the 6th ranked QB in the draft class, and the first 5 QBs withdraw their names, that doesn't catapult Beck to the first round, and the top of the draft board. The draft works in this way: does player X have a first round grade. Currently, Matt Miller (ESPN Draft analyst/SR draft analyst), only two QBs have first round grades as of January 3rd (Mendoza and Moore). If Moore elects to stay at Oregon, that doesn't propel Simpson to the first round and selected by the Jets.
And it's more likely Moore remains in the draft and his agent simply tells him that he won't play for the Jets.