And to my knowledge the hardware buttons of a Ledger Nono are completely software controlled. The buttons are not directly wired to the Secure Element where most of Ledger's firmware magic happens. The MCU controls the display and the buttons and proxies user interactions to the Secure Element. It's the firmware that decides what to do when you press a Ledger button. As the firmware is a black box what exactly prevents Ledger to not need your button press? ... Exactly: nothing! It's their secret sauce code...
This is the exact point I've been making:
Given that a simple software update means the secret element can now export private keys, then a simple software update could make this feature mandatory, or could remove the need for any physical button presses, or could take everyone's private keys without their knowledge or consent. The whole point of the secure element is moot. The entire security of the device hinges on non malicious software.
I doubt Ledger would ever admit that they could remove that physical confirmation any time they want, but are you both 100% sure that's how it works? You have no code to back that up, the same way Ledger hasn't made any available to show that they can't. Can the user's confirmation really be worked around that easily, and if they have malicious intentions, why would they simply not do it instead of telling us that they will?