There are people who feel financially insecure even with tens of millions in their accounts, and then there is a friend of mine who walked away with $1.2M after selling his house during the dot com run-up and moved to Boise, IA. He's been there ever since and really loves it.
In my experience the people who "can never get enough" are the unusual cases, not the folks who just happen to like what they are doing and it pays well, but people who focus all of their energy on increasing that number at the bottom of their portfolio account.
There are a whole lot of people who are "retiring" than you read about in the funny papers. They don't call it retiring of course, because retiring carries a stigma of sitting on a porch sipping mint julips and telling stories about the 'good old days', but they feel bad about calling it 'full time vacation mode' which is really what it is.
[1] Generally technology people of course, and generally through stock they owned in a company they worked at as an employee.