I think the reason that you are seeing delta looking like alpha now could be that to start with there is a substantial cohort who are more susceptible to it. They get sick first. They're done. Now we are only left with the more resistant people.

Isn't any nation doing random sampling of people with no symptoms to find out just how many of them are sick, unaware, and out there infecting others? I can't find any studies. I would think that this would be something everybody would be interested in knowing, so this puzzles me.