A quick search would show you countless articles of us citizens illegally living in Mexico. It’s an open dirty secret.
Provide a link -- would be interested - but if you read my post on Mexican immigration laws and Constitution -- they would be put in jail.
Your statement is not based on fact and you were too lazy to even try to back it up with fact or links. I don't think there is any American who would need to "illegally retire" in Mexico. People who retire in another country have a lot of money and wouldn't need to immigrate illegally into Mexico.
Your statement is absurd.