That person fails precisely in the "have a small safe income to pay your bills" part.

He also horribly fails at updating. His whole plan seems to be writing emacs tutorials and selling them for money. (I didn't read the whole website, maybe there are more plans, most likely not better.) Besides being an obviously bad business model, he is actually very bad at writing; which means he can't even show his tutorials to a potential employer and expect to get a technical writing job or something like that.

This is something that cannot happen in the "library" scenario. At least not soon; maybe a few years later, if the library job becomes unavailable. On the other hand, it can happen in the "moving to a larger city where no one responds to my job applications" scenario, if the potential employers keep not-responding, there is no income, and the rent goes up. But I didn't want to discourage; it only takes one job offer to get out of that situation.

For another horror story, I personally know a guy who decided that he will refuse all programming job offers until he gets an offer using SmallTalk (because "Java is only for idiots", although he made decent money from it in the past). He had a lot of money when he decided to do this, now, a few years later, he is homeless. True story. (If you ever visit Slovakia and find a homeless guy with a notebook, that's probably him.) Again, he failed at having a small safe income. That's the point. You either have some way to pay your bills, or you quit your plans before you hit the bottom and break your legs.

Most people seek "paying your bills" and "making a carreer" in the same package. It's probably a good strategy in many cases. But there are other options, too.

I knew a guy who worked for government. He told me he only worked one hour a week. (His work consisted of receiving a Word document with some information, converting in to HTML, and publishing on the website.) He spent rest of the time browsing web. When he discovered that the new version of Word has a "save as HTML" function, so his one hour of work becomes literally ten seconds, he became depressed, and later changed jobs. I kinda didn't understand him. If I had that job, I wouldn't quit. Instead, I would use this free time to do my hobbies and projects. Like translating Sequences, making websites for my friends, writing textbooks, learning new programming languages, making computer games, etc. And I would gradually prepare an exit plan, so that one day I would quit the job, but the next day I would activate AdSense on the dozen websites I would have made before, and activate purchases of virtual goods in the mobile games I would have made before. (To make it legally okay, that I wasn't making money while working for the government.) These are lost opportunities. And maybe... maybe not... the library is one of them.