Because MANY but NOT ALL aircraft share ALL system. SOME share similar systems SOME don’t.
Let’s say you fix a bug in the G3x then the it’ll have an effect on the VL3 and TBM but for the Caravan wouldn’t make a difference because it uses the G1000. And on top of that, the CJ4 and A320 don’t use garmin systems at all. So their systems would have nothing to do with what you touched in the G3x. Then they are the 430s and 530s… etc.