Should there be a limit to what ex presidents, ex first ladies, ex congressmen and other ex public officers could earn for giving a speech?

Like for instance the weekly median salary in the nation?

Otherwise, even though they are out of office, it seems so much ex-post rent extracting clientelism.

I mean does it make any sense to compensate one speech given to a few, with sometimes something that could sound like the salary paid to him by all for a full year of services to the nation?