When thinking about WoT, we have to consider where Nostr is headed. There is a social WoT usecase & a commercial WoT usecase. The social usecase is pretty much already solved because Nostr discovery is inherently difficult.
There's little risk involved with simply following someone & you can't have trust without someone taking some risk. We humans assign a level of trust to our relationships, it's not a binary assignment.
If an npub is followed by an arbitrary number of npubs that I also follow, then that's probably enough for me to also follow them. To risk wasting time reading their nonsense, which can be easily solved by an unfollow and/or mute.
Would that be enough to send them sats for goods/services? Maybe it's enough to take a small risk with them. What happens if I feel they've acted poorly? How can I warn my other followers to be careful with them in the future? It's the transition from social to commercial trust that is difficult to solve.
If an npub that I trust creates a nym npub for the purpose of selling, how does that npub generate trust? How can I use my reputation to help support them & their business?
This isn't about eliminating risk, just reducing it. It's about assigning a cost to acting unethically. To minimise the value 1 npub can extract before they're exposed.