Although anything and everything can change in this world, Jet2 had every opportunity to go for Gatwick slots when Thomas Cook failed. They did not even apply (where others including BA and Wizz did) and so one has to assume that's a clear statement by Jet2 of "no interest in Gatwick", albeit six months ago and not today.
Or maybe they weren't interested in the size of operation that could be launched from a share of the TCX slots, didn't have the resources available or a number of other reasons other they had no interest.