@dalias @whitequark @glyph @mcc Through transparent E2E and synchronization b/w devices. This mythological technology that they are... you know... widely using already.
Also: You yourself brought up password managers and generated unique passwords. Which have literally the same problem: If you lose access to it, you lose access to the sites you've logged in to. And the high # of log ins make it unrealistic to memorize or write the passwords down. If you really think that's what they're do then you're widely out of touch with the general user's reality.