Earlier quoted context omitted.
Here, let me give more "less painful" advise: 1) Don't quit your job, start consulting on the side 2) Don't quit your job, start a product on the side Both options won't cut paycheck. Take calculated risk. OP is no longer a 24 years old super smart developer.
So I can't speak to his particular situation. But in general I disagree with this. I think quitting the job is the most important part. Consulting is the safety. "Leap and the net will appear" - John Burroughs
Consulting requires networks and connections. If the person stick too long as a "Senior Software Developer" and rarely meet non-geek human being (potential customers), it'll be a while before the person can get a well-paying less-stressful consulting offers.