If you no longer hold a position in government at any level your security clearance should be revoked.
The Swamp is thick and the Swamp is deep. It's been building for over 50 years, probably longer than that.
Trump's got an enormous task ahead of him. Draining the Swamp will probably take well past his two terms.
What's been done so far is Triage and hot topics which needed immediate attention. However, the first 12 months were taken up in discovery - discovery of who he can REALLY trust in the Beltway (they are few).