I imagine it’s like everything else, you can only realistically verify against a random sample. It’s like trucks passing a border, they should ALL be checked but in practice only few gets checked and punished with the hope that punishment will deter others.
Here if 1 chip is checked for 1 million produced and there is a single problem with it, being a backdoor or “just” a security flaw that is NOT present due to the original design, then the trust in the company producing them is shattered. Nobody who can afford alternatives will want to work with them.
I imagine in a lot of situations the economical risk is not worth it. Even if say a state actor does commission a backdoor to be added and thus tell the producing company they’ll cover their losses, as soon as the news is out nobody will even use the chips so even for a state actor it doesn’t work.
I must express myself quite poorly. It is not a point about technical knowledge, in fact if you were to know more about the topic than I do, I would expect you to even more be upheld to higher standards and thus not promote a bad solution, even more so assume it’s the only one. I can’t imagine that even a PhD student who is supposedly at the frontier of knowledge in their very narrow field would assume no alternative is possible, or will ever be. This even more the case without having both a complete understand of the landscape but also about OP’s actual needs, which is probably hard to express clearly and thus leading to a lot of assumption. Here maybe a simple loud alarm from a BT speaker going out of range might be enough.
My whole point is that abandoning hope, and leading others to do so, is worst than actively finding for a barely OK compromise.
Anyway I don’t want to invest more energy on this discussion unfortunately so simply wishing you the best, thanks for the clarifications.