But modern hub gears are no longer standard, and relegated to specific use cases.

There's a lot of friction in hub gears (at least the one I rode a decade ago), and fixing them is generally impractical.

Shimano Nexus is from 1995. What did you ride twenty years later, in 2015? I call BS on the friction argument.

It's true that internally geared bikes are common, especially in Europe. But internal gear hubs that are coaxial with pedals are almost unheard of. The only production one ever is the Schlumpf Unicycle hub, which costs $1500 and only a few hundred have ever been made. It also has only 2 gears. It's certainly possible to do, but I have doubts about a company opting for that incredibly expensive option of creating a new hub instead of reusing standard bike parts.

> In wheel gears have been in use for over a century very successfully.

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.

...what? There's a whole bunch of manufacturers, so many that there's an entire Wikipedia page disccusinge them at https://en.wikipedia.org/wiki/Comparison_of_hub_gears. There's at least 8 different manufacturers on there, some with many different models. Some were introduced as recently as 2023, so it's hardly some abandoned legacy technology.