It's very much a hobby, like audiophiles, but also like tricking out your car. It can be expensive. It's more than the average person needs. It's fun picking out parts and being part of a community.

There's also a perspective bias that most mechanical keyboard content you see is not made by people who found a keyboard that made the wrists stop hurting and then went on with their life. The people enthusiastic enough to make content are also the people that have a bunch of tricked out keyboards.