[ilamont]

Nobody in my family - parents, kids, spouse - knows what an authenticator app is or would what to do if presented that as an option, although my teen could probably figure it out.

For everyone else, it would be a cascading series of installation and password and app switching and immediacy problems. This would create a great deal of frustration, and ultimately a call to family tech support (me) or the service provider if human tech support is an option which is not the case for many companies such as Google and social media firms.

[brewdad]

The biggest hurdle to authenticator app adoption for the masses is the one that only bites you a year or more down the road when you get a new phone. If you didn't transfer your seed info over to the new phone before trading in the old one, you are locked out of all your accounts.

[slothtrop]

for this reason I've kept storage in keepass and backed it up in more than one place, but admittedly it's possible to lose everything. You need to expose yourself to a little more risk just to mitigate that possibility.

The other issue is that many smartphone owners don't have a computer they would back things up to. Just "cloud".