PKI specifically is an all-or-nothing scenario. This is all why Intel does the same with the ACM in all their CPUs. And AMD with their AGESA (which went closed a short while ago).
There is only a single scenario I can think of where there might be a 'have it both ways' situation, but it's just worse than we have now: you have to identify yourself as the owner, the company has to keep track of that, and you can only sign public keys for your own components. This, however, creates two problems:
1. A company keeping track of every user (no need to come up with a clever comment about "they are already nothing that")
2. Users can be coerced (has already been done with thefts and activation locks) and this weakens the ecosystem as a whole
At this point it doesn't even matter how intentional or not digitally signing components is, it is an effective security model and it works better than anything else.
Everyone loves complaining about everything they don't like, especially on the internet, but so far the amount of realistic and effective solutions are NONE.