[ebbv]

I'd say 80% is already a vast majority? But ok if you think 20% is too high we can go crazy and say half a million phones have this problem each year. That's still less than 4% of the 6S/6S Plus sold opening weekend. Let alone whatever the total 6, 6 Plus, 6S and 6S Plus sold over the last two years is (which I couldn't find a figure for from a quick search.)

The point is, it doesn't appear to be a widely occurring problem based only on what this iFixit report contains. Maybe there's more data out there that indicates it is more widespread? If so this article should have had that data.