Exactly what I tell my startup friends. I know people who run design consulting firms and pull in $300-500k/year in profits. Some run SEO/SEM marketing agencies and do similar figures. They give themselves generous salaries and own nearly 80-90% of their businesses which, on paper, are worth $4-5M.
That's definitely very, very well-off, if not F-U rich. And it's very "safe", unless your $1M in revenue hinges entirely on one or two clients