Business value: Why blockchain over SSO/AD?

[MukeshMogal]

Indeed a really nice idea of having a decentralized store of identifications for authentication but the problem statement could be articulated in a better way. I think using blockchain for authentication will increase user adoption and productivity rather than saying it will "provide granular control of identity information to any organization". self-sovereign identity would solve a lot of regulatory problems (like GDPR) for many organizations. Nicely explained in the following article Decentralized Identity: An alternative to password-based authentication.

Current authentication systems using SSO and AD are quite secure and provides organization control over what data to be shared with third-party service providers. So why would any organization adopt for decentralized authentication? Will this Implementation discard password-based authentication?