There are already significant limits on post-employment work by government employees in 18 USC 207, and these limits are enforced. It's a misdemeanor to violate those restrictions, and a felony to do it willfully. Employees are trained on this statute every year, and prior to separating or retiring from employment they are specifically counseled about this by government ethics attorneys.
It's the industry people being hired directly into FAA leadership positions that concerns me more.