You are getting it backwards.

Do you know always who is on the other side of a purchase that you do online? I can bet you don't, yet you still do business because you trust the intermediary (credit card provider, Amazon, whoever) to ensure that both parties are getting what they want.

Blockchain and "trustless" systems are there for people who want to make business but do not have these intermediaries, or when the intermediaries themselves are not trustworthy (corrupt governments, inefficient companies, etc).