You convince the employee to port "your" number and they do so and then you reset that accounts password?
https://www.wptv.com/money/consumer/phone-porting-leads-to-s...
HN demanded for such security holes to be disabled and prevented - what changed since then?
If the worst thing that people could commit in this discussion is hypocrisy, I'm sure they're willing to step over that line.
For me, the larger threat is that someone impersonates me and takes everything I have. If I lost my email, it would be a nightmare but I could work around significant portions of the system. For my cousin, the larger threat is losing her email, as she has no significant assets to steal but could run into every problem in the email.
There are likely people in the middle as well, and other threat vectors. (For example: caregivers committing fraud, dementia, state actors, and 20 other we could brainstorm pretty quickly.) Perhaps the right answer is that we need 20 different services that can segment. Perhaps the problem is that some sectors aren't profitable: maybe we need a grant for emails for poor people with a circle of trust.
I don't have answers. Maybe we need a collection of people to think deeply about this problem.
It's a lot easier to implement reliably due to the requirement for everyone to have ID cards though (and the ID cards carry your residence address).
As for post offices, they aren't eligible because half the government is actively trying to kill them.