Not to put too fine a point on it, but your attitude is exactly the kind of thing he's talking about in the linked interview. Mega growth and mega profits are one measure of success. A life with low stress and plenty of time for your family (and by the way, making all that possible for your employees, too) is another one.
But I would have liked to see him say "we could have been far more profitable, but we didn't care about that, so we limited hours and didn't hire salespeople." Instead what I hear him saying is "we are the best business we could be, because we limit hours."
Rather than the main focus being happiness, I think the main focus is:
Are you building something great?
And he believes maximizing happiness and job satisfaction is a core component of achieving something great.
Is 'true potential' only evaluated based on attainment of maximum dollars per day of business? I don't see how he has failed anything but living up to your idea of achievement which, frankly, seems a lot more shallow then his.
Do you have logic? Data? A Delphic oracle? Perspectives into a parallel universe where they hired a sales team? Something more substantial than feelings?
37signals once built software I loved. Salesforce builds software I loath. 37signals could have been great -- a Salesforce with wonderful software -- but the CEO is happier to pat himself on the back and brag about laziness. That's my logic. Do you feel that I am incorrect?
Yup. That's exactly how I feel. I don't know why you're bragging about your incorrectness all over the internet, though.
[1] From the article.
[2] http://37signals.com/svn/posts/2593-official-pictures-of-our...
As far as the car goes, very little info on that and additionally you are drawing a conclusion as far as DHH's money which could have come from other sources as well as 37signals.
I'd say it's equally likely that 37Signals could have failed utterly in rapid expansion as they could have succeeded if they made their moon-shot.
Everyone has infinite potential.