Trust isn't really a feature of blockchains, nor is it a byproduct (or "software primitive") of blockchains. Bitcoin was designed to avoid a need for trust, so it really just steps around the issue of trust in a distributed ledger. This is a critical misunderstanding that a lot of people are still preaching and perpetuating. You can't really build systems that rely on trust on top of a blockchain, and those who have…
I'm not sure what you're saying here. BTC wasn't designed to avoid the need for trust. It was designed to incentivize the network to act in a way such that you can trust it. That's how it provides trust.