My point still stands though. They can't force them to open up their trade secrets.
If the government can make a law that says someone can't sell a particular product (Like say, children's toys with razor blades in them) why can't the government pass a law that says that if a company sells a particular catagory of product then the company must open the product up if they discontinue the product or go out of business?
You can't, but governments can. There are laws that protect IP; those laws could be modified to say that, if you decide to stop supporting a product that relies on your IP, then you must provide the means for individual users to support it themselves. That doesn't even have to mean giving up your IP; it could just mean designing from the beginning with the idea that a company won't last forever—but that'll never happen unless it's forced by law.
It would be straightforward to mandate such agreements be included with all IoT device purchases.
Ideally, they'd also be triggered by acquisitions or modifications to privacy policies. I can dream, right?