Given the EU is mandating replaceable batteries very soon we might see some momentum on this.
These consist of a standard cell with a protection board stuck on the end, and usually a smaller raised positive terminal. This adds 3-5mm to the length, and temporarily breaks the circuit in the event of over-voltage, under-voltage, or over-current/short. There's no written standard, but most brands are making pretty much the same thing, and they almost always interchange. Safety does not require it to be proprietary.
Here's an example from a flashlight manufacturer: https://www.skilhunt.com/product/bl-135-3500mah-18650-protec...
Here's an example from a third-party battery distributor: https://illumn.com/18650-keeppower-p1840c-4000mah-protected-...