Patent examiners top out at like $140’s pretty much. Nobody that’s GS scale makes over $160. Starting salary at big law firms is $180 + bonus. So you have a fair pint there.
Also, as far as time bars, the PTO does something like this. Former examiners are not allowed to apply for a patent for a term after they leave. Doesn’t really solve the problem, but it’s something.
The USPTO also bars former examiner's from working as an attorney on cases in the area in which they previously examined for two years after they leave the USPTO. I do not know how carefully this rule is enforced.
On the downside - restrict employment opportunities for X years after being in a specific position.
Clearly both have issues, but regulatory capture is a problem worth solving.