In tradeoff engineering, maintainability over the long term is one of the many variables to optimize, and finite resources need to be alloted to it.
When I read this article I get the feeling that it's more likely that he is obsessing over maintainability over the long term while his app has a user count of zero. This malady usually comes from the perspective of being a user, one finds that the experience of writing some code is a "bad experience" so they strive to improve it or learn how to build a good "coder experience", the right answer is to understand that one is stepping into the shoes of the plumber, and it will be shitty, just gotta roll up your sleeves.
Don't get me wrong, there's a lot of wisdom here, but to the extent that there is, it's super derivative and well established, it's just the kind of stuff that a developer learns on their first years of software by surfing the web and learning about DRY, KISS and other folklore of software. To some extent this stuff is useful, but there's diminishing returns and at some point you have to throw shit and focus on the product instead of obsessing over the code.