>but standard enough that people by binned playstation 5 motherboards to use as computers

That doesn't mean that all the features are enabled right from the factory, or that the compatibility with already existing features is lost.

Modern chip's security features are pretty complicated and include hardware patches, hardware debug authentication, multiple provisioning states (and multi-key hierarchy for that), RMA states to clear all the private information, etc.

>Switch runs on basically the same Nvidia Tegra CPU/GPU as multiple android tablets.

Yes, and the one which got cracked with a bootrom vulnerability ;)

That's a pretty working motivation for a chip company to improve their chip security when the company as beefy as Nintendo tells them that their chip is vulnerable they're losing money because the customers can play for free ;). I'm pretty sure patchable bootroms started to be common only after Switch hack.