Yeah, it sounds like there just legitimately are 50K people who are in this niche. Maybe the fact that people might assume there are fewer is why there was a gap in the market for the author to fill!
Also, and this is the neat bit, 50k people actively looking for recommendations on online communities
If you like building keyboards, you’ll end up using a couple of these.
I have 6!
I think this is the Big Thing when it comes to making things - underestimating the market. Mechanical keyboards is a multi-billion industry, and building them yourself is a percentage of that.
That said, I wouldn't be surprised if this product managed to end up in the supply chain for a lot of the keyboard manufacturers, which would be a huge boost to sales volumes.