I worked 60-70 hours a week for 6 months and destroyed by health ( actually programming for 50+ of those hours, tracked time since it was billable hours for a consulting firm). Finished the project by the deadline I was hired for, but quit soon afterwards and within 2 months I was in the ICU, and then in and out of the hospital several times with some serious chronic health issues that I'm still recovering from 2 yea…
That's what I do. I started out freelancing and eventually I found a client who eventually needed buy all my available time. 30/h a week, at a salary that feeds me fine.
For reference, I do PHP and linux admin for WordPress and some linux admin work. It's not super fun, but I work for a tiny company and have to look at all parts of a bunch of rando tech stacks (like, moodle, drupal, java applications, mail servers, etc and everything from firewalls to CSS for IE10).
It doesn't "scale". So there there is nothing to "disrupt". I just work with a couple of smart people who do good work, and if we tied to make the business grow substantially we'd probably just work more for the same amount of money, so we are just really selective about what jobs we take. I think. I don't have a great analysis of what makes it work cause I am in the middle of it.