The expensive customs scene is really just people who don't understand how trivially simple those customs are.
There's nothing high tech / advanced about 2.5D milling. I've tried to explain this to the keyboard section in the past, but the average consumer is too poorly educated to understand the lack of value proposition.
2.5D keyboards are the machining equivalent of nailing 2by4s together in your basement.
In many ways, advances in PCB / induction switches / rgb far outstrips the utility of expensive cases people spend most of their money on.
It's the same crowd that spends $500 on case/fan/rgb/psu, when $100 will do the same thing, w/ a +$400 GPU almost doubling the performance.
You take your $600 custom keyboard, put it in a cheap plastic case, $580 into pcb, switches, That's like, a freaking computer in the keyboard with its own CPU RAM GPU, Runs Crysis at 1080p 60fps.