It was a valid point. There's a significant performance/weight reason most of the devices with non-removable batteries and built-in charging are using Li-ion instead of NiMH.
Getting a bunch of consumers used to buying spare Li-ion cells and using external chargers might be a non-starter, but it's possible to have both onboard charging and removable cells so the upgrade path is there for those who want it.
I've had a series of Canon powershot cameras that have all used more-or-less the same Li-ion cell design[1] and I've been able to swap batteries with them. They're big enough that third parties have even offered replacement batteries.
There is probably room for standardization of a compact, rectangular, rechargeable battery of roughly those dimensions. Is someone pushing for it?
I don't think anyone is pushing for that, though sometimes a company will design a device around another company's battery design. There's quite a bit of small photo/video lighting that uses Sony NP series camera batteries. Those are just a pair of 18650s in series inside a plastic box.
It seems to me the size of the G7X could have been designed around a 14500 cell instead.
Getting a bunch of consumers used to buying spare Li-ion cells and using external chargers might be a non-starter, but it's possible to have both onboard charging and removable cells so the upgrade path is there for those who want it.