Also something to keep in mind in the future: Old people have no reason to fear prison, they will die before they can get convicted.
The odds are too low of anybody getting meaningfully punished while they get to openly setup their entire family for generations using means and information not available to any normal citizen.
And while not guaranteed they are statistically more likely to suffer age related cognitive decline while still in office.
It's nice and clear, has obvious motivation and obvious sourcing.
Also obvious incentives: e.g. after your political career you will live with the system you helped build.