I've been shooting with one focal length (normal lens that is) since my mother put the first roll into Smena 8M and gave it to me, somewhere around 1991 IIRC, until acquiring wide(-ish) 37mm Mir 1b and borrowed 20mm Flektogon from a friend, both somewhere around 2002. Am I a better photographer because of a decade spent this way? Nope. I feel like some years were wasted, some good years, that could have been used wiser and some opportunities were lost and won't happen again. I haven't wrote a poorly illustrated blog post about being a "minimalist" for 20x longer, than the guy.
Some people with their TLRs use this approach through 99% of entire professional career. Is it liberating? I'd say it's normal: you just focus on your work, same kind of focus, as when tackling two lenses more in a bag. Missing some opportunities available only with wide angle lenses is a waste sometimes, but it's nothing to cry about. It's the photo, that matters, the story it carries within, the truth about human life an image tells. This guy didn't quite got it, still being focused on himself, his skills and style, his creativity and vision and paradoxically, his gear, cause the single camera and lens mattered for him more, than relentlessly expressing whatever his vision was.
In 2012 I've closed down my blogs just to have more time for photography, rather than writing. I got rid of a serious amount of unnecessary gear in 2013. Was it liberating? Nope, I've only liberated my shelves.
I adore mindfull minimalism and I love the shore, but this guy sounds like someone, who either is in his infancy, not serious, or seriously lost the plot - nothing bad either way, just nothing to write about, apart from "yupsie, I've learned a thing or two, cool exercise". The very fact, that this poor guy dropped 6 months of project because of being busy, simply tells it all - either the project or the author wasn't serious, or the project was done and he would gain nothing continuing it, or it wasn't important enough to pick it up and continue. So my final conclusion is the author wasn't quite honest about himself.
But on the other hand, I know this were well spent months. Thumbs up for the inspiration it gave me this way or another.