I would start with the idea that it is not right for the same person to be the CEO and the Chairman of the Board for a public company.
The point of a corporation is to be bigger than one person, if you can afford a CEO, you can afford a separate Chairman, so you get another point of view involved and I think it is better for everyone, I mean the shareholders, employees, customers, and the even the CEO in the long term.
That does not solve all the problems but it is a specific step that would improve trust in governance.
But what is the incentive for a company to pay their CEO less?
Perhaps explore why CEO pay is high to begin with.
It's all well and good to say "this is bad" but it's more useful to have a discussion around why specifically can/should change.
In the free market, salary is worth whatever the buyer is willing to pay.