The only gear I've seen in stock was for a bafang. It wasn't clear which model bafang motor it was for, there are several.
The geared hub motors run from $150 to $800, so it is not a tragedy if one wears out. I wore one out (gears) in ~4500 miles, which cost me $221. The replacement motor had more of a reputation, and cost $740. I hope the second one lasts more than 3 years. That replacement cost included a built wheel, controller, throttle. It only took me 2 afternoons to convert from one hub drive to the next. One afternoon was building a new mount for the incompatible second controller.
The people that can really be hurt are bike owners that had a proprietary battery with patented configuration and connectors. Replacements batteries can be $1000 up. Batteries are a ~1000 charge item. People that live in California Colorado & Ohio can transport their old batteries to a rebuilder. The rest of us have to throw the old battery away or drive 1500 miles, LiIon batteries over a certain size can't be shipped. Only by trained, certified, hazmat shippers.
One certainty for us pedal bike converters is wheel size and fork size. Both are standard. Even other vendors will follow those standards. I used a generic battery with standard 14 ga wires exposed. I cut off the OEM connector and use standard dorman crimp terminals, industrial grade. I've had no power failures in 6500 miles.
Happy shopping, & later maybe riding.