I think the availability of digital authentication methods significantly varies by country. E.g. here in Finland TUPAS (https://en.wikipedia.org/wiki/TUPAS htt

I think the availability of digital authentication methods significantly varies by country. E.g. here in Finland TUPAS (https://en.wikipedia.org/wiki/TUPAS https://en.wikipedia.org/wiki/TUPAS) is used by both government sites and private companies. It relies on two-factor bank credentials that almost everyone here has. Two-factor has been standard since online banking became a thing in the 90s and all banks are part of the ~10 bank groups so there aren't any small unsupported banks that I'm aware of. Government sites also support ID cards but no-one uses that option. I believe some other countries have working, but different, digital authentication schemes as well. Maybe Estonia and Belgium? These don't work over the phone, though, and asking for address and your identity code (or some part thereof) remains a common over-the-phone "verification" method, at least here. So the identity code / social security number issue still exists, at least to some extent.