This design is unstable and expensive to produce with a complicated in wheel transmission. It is novel, but almost certainly more expensive and less reliable than existing designs.
There's a lot of friction in hub gears (at least the one I rode a decade ago), and fixing them is generally impractical.
They've been barely viable the whole time. Sturmey Archer are the last maker in business; they went bankrupt a couple of decades back and for some years there was serious concern that manufacturing would never resume.
I’ve ended up with some electronic road SRAM which is seriously quick in comparison (except for the slow rider), but do miss the smooth internal hub and the stationary gear changes.