Is it low though? I'm not sure my parents could figure out how to use an authenticator app.

I'd rather just have a whole list of allowable factors and the opportunity to configure one or more of them depending on my personal risk tolerance.

An authenticator app just has the codes and the sites. SMS has the codes, all the previous codes, all of your other SMSs. Plus the messages come from a 5 digit phone number that has a similar format to the 6-digit code you're supposed to enter. The whole system is byzantine IMO and the authenticator app has a much simpler flow. But, you know, I recognize that not everyone may experience it the same way.

I'm generally curious if people think there's a simplicity to the SMS approach other than just familiarity with something that's awkward.

The real problem IMO is not that it's hard to use an authenticator app, it's that the authenticator app provides an actual secret. There's less of a backdoor, so customers can lock themselves out. The downside of the backdoor is it's a security risk. The upside is that managing private keys is a nightmare and nobody wants to force their customers to actually manage private keys.

If you wouldn't advocate banning deadbolt locks just because vault doors are better, why advocate banning SMS 2FA?

I don't know that I'd go so far as saying that a ban is the right thing, but something is needed.

I imagine even if it were easier, you would see low adoption, because “I’ve never been robbed but I have locked myself out, does this mean I can’t call a locksmith anymore?” Would be top of people’s minds.