Lots of potential reasons. Multiple suppliers that build “the same” part, but that differ in some “seemingly unimportant” way. Think generic drugs vs brand drugs.
Software is what glues everything together, but the individual components may be different across cars; I don’t know. Or a component may not perform to spec. Or a wire is pinched or loose.
Lots of issues can present as “the screens are blank” or “my key doesn’t work” which would feel like software but might not be.
I’m guessing that hardware differences and/or physical issues may be just as likely a cause. Just a guess though.
To be clear: that doesn’t mean it
isn’t software. At the end of the day, the “glue” can mitigate for most issues with communication or components; but they have to run into or find the bug before they mitigate for it. So the solution may still be software (except for a pinched wire or loose connection, etc), but the
cause may be hardware.
I hope I made sense. It’s early