I think "hardware is as hard as you make it" would've been a better title. The author made the smart decision of keeping things very simple on the hardware side, and that happened to be possible for the kind of product he wanted to make.
Interestingly I've heard a very similar story and sentiment about hardware vs software from another single-person maker (also a software engineer by trade) of a hardware product, also in the music space. And this one was comparatively a more complex product on the hardware side, and did face some supply challenges during covid and tariffs, forcing at least one redesign and price raise. But in both cases, I'd say they made smart choices about keeping the hardware simple. By not pushing the envelope on that front they gave themselves the freedom to invest a lot of time and effort into the software. But not every hardware product is like that (which the author also does acknowledge).