Why Nintendo is so stubborn when it comes to media formats?

[TheWPCTraveler]

Because you could effectively upgrade the hardware with cartridges?
I mean, the most effective argument for cartridges, ever, has not been mentioned when once in this thread.
Think about Starfox, about various Mode 7 titles on the Super Nintendo/Famicom.

I mean, I'd think that the Expansion Pak would've been more effective had Nintendo found a way for it to fit within the cartridge itself.