Title (original from TFA) is very misleading. The study is too late in the process of setting up 2FA. No one in the study was motivated to set up 2FA in the first place. This is "merely" a UX study that benefits Yubico. It doesn't address (at all) why people do or do not want 2FA in the first place.

To use my own insight: regular joe does not want to buy an expensive product and install some hardware. (the "cheap" $20 ones are literally worse than useless. but even $20 is too much.) 2FA's future is in touchID (integrated into touch bar on mac) and push to a phone app. The latency of push to a phone app is more acceptable than the confusion and vagary around adding an expensive usb key that you don't understand and then doesn't work on your mobile anyway.