That said... one quibble: I'm not concerned about the computational resource point. People demonstrably pay for and self-host millions of hashes worth of monetary network compute cycles.

Once properly decentralized and subjective trust systems begin to prove their importance as one of the only viable ways to manage and scale human relationships/society in the context of complex, distributed networks, I can imagine that people will be willing to shell out a few watts and bytes to run such infrastructure.

Once it becomes clear your options are: What I just described; "manual, hand-curated trust"; or MEGACORP ALGO, I think the right people will come around at the right time ;)