OK, it's just an analogy, to make a broad point about the approach to design and construction. But you absolutely can design software in that way - I do it, and it works very well. It's not easy, but as I said in another comment, it delivers robust solutions that are nonetheless adaptable to change and easy to maintain. By contrast the 'agile' projects I've worked on were either a tangled mess, or else failed spectacularly.

> This isn't how writing code works

Maybe that's not how you write code, but there are many different ways to paint that particular fence, no? I've been coding for a long time and for me, this is the approach that I've landed on that's the best I've found so far. To me, the idea of feature-led development is, to put it mildly, nonsensical.