Do you have statistics on the number of people who do not have smart phones but do have these other devices? I am not sure the intersection is as high as you imply.
The only people who don't use smartphones and don't have an iPad or similar tablet and don't have a recent computer... probably don't benefit enough from 2FA to justify the risk of account lockout.
In my social circle, the people who don't have smart phones are:
- People with disabilities that make reading from a small screen or texting a lot impractical.
- People who work in harsh environments who want something more rugged than a device made out of glass.
- People wary of the distraction of carrying around an entertainment device.
All of these people except one also have an iPad (especially the first group, as the larger screens help a lot). The one who doesn't does have a Dell XPS 13.
