They were already rich when they agreed to $1 salaries, and they accept compensation in the form of stock (as you mentioned) which drives them to make the company as profitable as possible so that they may rake the proceeds in.
Jobs also got in trouble for "timing" the date at which the stock options were pegged for himself and his executives, which means that with insider knowledge of performance he was able to peg the most profitable "buy" dates for the options and thereby enhance executive compensations dramatically. I forgot the term for this.