What happens if you don't have a smart phone? Can you just not log in?
The reality is that not having a smartphone means it's increasingly difficult to access any number of services.
You have to provide old-fashioned alternatives to all the new whiz-bang high-tech shinyness.
Surely the subset of people who want "Online" access and don't have a mobile phone and don't have a webcam is tiny. Those people can use the "Offline" access, whatever that is but I assume there is some system that predates the internet that allows people to get access to their IRS info.
Then this change doesn't affect you? What am I missing?
From the sound of it, we just need to find a good 4-8 hours where we can do nothing but verify our identity. Then when that fails, we can spend a bunch of time finding other documents, then show those and hope they work. Hopefully the IRS is open on weekends...