It's complicated. Nowadays we have shortage of electronic components and it's difficult to know what will be not available the next month. So it's obvious that manufacturers have to make different variants of a product that can mount different components.
That complicates a lot of things. You are basically making a new product, with all the complications (and costs) associated with it. And where do you stop? What decides if it has impact or not? If I change the brand of a capacitor do I need a new model? Of course not. If I change the model of a switching controller? Well, still shouldn't change anything, but let's obvious. If I change another integrated circuit (i.e. a small SPI flash used to hold the firmware, or a i2c temperature sensor, or a supporting microcontroller)? Likely doesn't impact that much.
