But wouldn't it be more fun programming on YOUR terms, not your employer/boss' terms? Even if that meant you had to spend a bit more time managing your business?
When you're running your own business, you work on the market's terms. The market is the most unforgiving, inflexible, demanding, and heartless boss of all.
But still, without that extra level of indirection of employer/manager between you and the market, the terms are not distorted and you have the freedom to interpret it in whichever way you want to. Of course, the consequences as well.
I prefer market being my immediate boss than anyone else.
Is it actually just "a bit more time"? I can only go by what I hear from others, but the stories I read in HN comments make it sound like that "bit more" is at least half-time work.
When I was freelancing, 35-40 hours per week, it was quite often that I only got to spend 10 hours a week doing actually programing. Anything over 20 was amazing.
You are forgetting, that if you spend 20 hours/week on your own business, then you would spend most of these 20 hours thinking and only ~5 hours/week coding.
Which would probably move your business forward very slowly.