You restated your position instead of addressing my question and then added irrelevant speculation in a different direction.
The issue with supply chain tracking is the sharing of information. If every part of the supply chain is hacked then you have all of the info. You also need to look at it backwards: instead of "who has X" ask "where did X go" which is easier to answer. It starts at the source, the factory, which can know which serial was in which lot. Then you know where that got shipped, etc.
Maybe occasionally units get "lost" but you do have error bounds on their location.
The issue with supply chain tracking is the sharing of information. If every part of the supply chain is hacked then you have all of the info. You also need to look at it backwards: instead of "who has X" ask "where did X go" which is easier to answer. It starts at the source, the factory, which can know which serial was in which lot. Then you know where that got shipped, etc.
Maybe occasionally units get "lost" but you do have error bounds on their location.