TSA jobs cant go away now that they exist. They probably never will. It will look bad for whatever president that does it because they will eliminate jobs and "national security" checks.
Everyone knows its a joke but we will keep doing it.
They could easily phase it out. They already have. There is already a rule that an airport can hire a private security company as long as it's approved by the TSA. They could make a small rule change that allows the private security to make their own rules, or just make some of the rules optional, like shoes off.
So we'd still have TSA agents in some places, but for example SFO already opts out of TSA agents. If they could opt out of the shoes off rule they probably would. At that point you've effectively eliminated the TSA without making a big deal about it.
Everyone knows its a joke but we will keep doing it.