Why wouldn't they? While sometimes it takes more time than a normal job would, it also offers a larger amount of freedom than a 9-5. And if you have a great reputation and a constant stream of clients, it is even better since you can pick projects and decide when to do them and in what manner.
On another note, Nela is quite an outlier! I've been following her work for close to 20 years now I think, starting from her HTML&CSS tutorials long time ago. Her blog was basically CSS Zen Garden for my generation, teaching us how to achieve beautiful things with HTML&CSS back in the age of Dreamweaver, inspiring many future developers and designers. She gave so much to the community through the years with her knowledge sharing that it still inspires me and motivates me to this day to share more. Nela, if you're reading this, thanks for all the great work!
It's not a prerequisite tho - I've arranged with multiple clients to work either 3 days a week or just a set amount of hours whenever I choose. And most of others I know who get into freelancing do the same - if you have offer for another project, and they can't wait until you're free, you can always recommend them to a friend/colleague.
On another note, Nela is quite an outlier! I've been following her work for close to 20 years now I think, starting from her HTML&CSS tutorials long time ago. Her blog was basically CSS Zen Garden for my generation, teaching us how to achieve beautiful things with HTML&CSS back in the age of Dreamweaver, inspiring many future developers and designers. She gave so much to the community through the years with her knowledge sharing that it still inspires me and motivates me to this day to share more. Nela, if you're reading this, thanks for all the great work!