This does seem partially misguided - Tim Ferriss himself does say that he spends a lot more than 4 hours a week on projects, because he doesn't see that as work, instead they are projects he chooses to do because he enjoys them (similar to the author of this post).
I think the title of the book is misleading, it should be "the 4 hour work and 30 hour doing something you like that pays your bills week". But it is a lot catchier to call it 4 hour work week, which in my opinion is the only negative thing about this book. From the title, you think you don't have to work and get enough money to do whatever you want, which is just wrong.
If you like your job at the startup, you did exactly the right thing, there is nothing better than doing the job you like and even get paid for it.
Exactly the reason why i didnt like the 4 Hour work week by Tim Ferris. I enjoy what i am doing and would rather improve my work experience if i wont find it enjoying anymore than to travel around the world todo "fun" stuff while other people earn money for me.