The problem is "oh, we're still supporting it, we just released an update yesterday that fixed an issue with kerning when selecting certain fonts on the built-in LCD. What do you mean 12 critical CVEs unpatched for years?" So now you have to define "supported," which will be lobbied to death by every vendor in the world.

Well, if the company is willing to live with the risks/liability of a still-supported product containing unfixed vulnerabilities then they're clearly not long for this world. Eventually someone will sue--no matter what the support agreement/TOS states--and they will win. Even if they don't it'll still be a pointless large expense for the business.

Then by the time you can see what they actually provided, the company is already bankrupt and if what they provided is non-compliant or otherwise useless, it's too late.

There is no excuse for not providing it from day one. And more than one reason to do it -- not only do you verify that you have what you need before they're gone, it allows people to find vulnerabilities sooner so they get patched before more people have the vulnerable device.

So any company that makes a device knows that all their proprietary work will become public if they end support -- that seems like a great reason for companies to not build devices.