"Pay" is long term. Comes in many forms. Forgiven loans. Grossed up real estate sales. Securities gains.
Jobs for wives, other family. Consulting. Legal work. Etc. Etc.
He's a lawyer. Municipal bonds need lawyers, and out of work political hacks often get in on that action.
Governments all over the place constantly replace bonds. Accountants/CPAs, rating agencies, etc.
It isn't called a Revolving Door" for nothing. Or DC Cartel if you will. Rubio could find hisself on boards, of Sea Island Corps, for instance.
Remember, while out of elective office, Kasich knocked down about $1 million per year.