I think about this a lot when using our corporate SSO tool.
When I hit the button to log into Slack, there are like, 3 popups in succession - the last one ultimately asking for my fingerprint. Then when I give it, there is a flurry of web pages that get loaded and redirects that happen until finally Slack pops up again.
There isn't any realistic world in which I check each window to make sure everything is happening right and I am not being MitM'd.
I'm a fairly technical person, and I would be unable to perceive the difference between a really tight security environment and my computer being hijacked.