[big-and-small]

It's not like consumer electronics contain top secret tech like EUV machines. All supply chain for firmware / software of 99.99% devices is very boring, contains absolutely nothing secret and the only reason why it's "difficult" is because IP owners was not bothered.

Once single EU / US legislation introduced that force manufacturers into opening end-of-life products all IP right owners will either immediately make it possible or go out of business.

Since everyone will be forced to do the same no one will gain any advantages.

[layer8]

I’m more thinking of patents and licensed third-party technology and firmware. There are standard tech stacks controlled by industry associations that you simply can’t open source because the association would sue you and kick you out.

[big-and-small]

These associations do not just exist in vacuum. They have licenses like this because law allow it and it's beneficial to them. Once there are regulation that demand something else they'll just follow the law.

Also it's not like every single bit of firmware / software must be open sourced - it's could very much be trade off where devices just need to be unlocked for modification and documentation made available.