I consider this a success story similar to an NBA star making it. So if 100k is very successful in terms of computer book revenues, then I’d say money should not be the main motivation to do it, as there’s better, more reliable ways to earn money in the software industry - working for any SP500 company will easily get you the same amount of money in less than a year, more or less guaranteed. I know it’s not either or…
working for any SP500 company will easily get you the same amount of money in less than a year Horses for courses, as we say in the UK, but working for an SP500 company means a boss, reporting, office politics, and spending most of the day doing things that other people want you to to do. If you're independently minded and want to break out of that world, stories like the OP's are nice to see.
I was approached by recruiters asking me if I wanted to work for Google in Zurich. I had to decline them.
I'm happier being a solo-entrepreneur. The best part is that I get to learn a lot of stuff about running a business, which was impossible when I was a employee.