Because it's not a simple problem. If you ask me for a loan, how do I know who I'm loaning the money to, who will be accountable for paying it back to me? If

Because it's not a simple problem. If you ask me for a loan, how do I know who I'm loaning the money to, who will be accountable for paying it back to me? If we have no prior relationship, then there's no pre-existing password I can use to authenticate you. What's your solution? A government provided security token of some sort, backed by a government database? A lot of people have all kinds of problems with those, from trusting government's intent, to their competency, to their security. A private party identity provider? Go start it.