Hypothesis: Outlook and GMail are so terrible at handling complicated conversations (they encourage top posting and make it impossible to reply point by point) that they have caused meetings to multiply when many topics could instead have been disposed of in email threads.

One symptom of this that many people have noticed is "send many questions, get an answer to one of them" syndrome. You can't see the list of the counterparty's questions, so you have to remember what they were, and many people forget while replying.

The people who created the Outlook and Gmail style of email had no experience with the tools that came before; they did not understand the power of quoted replies, and ideas like automatic sorting of email were things they reinvented thinking they were new.

I suspect literally billions of dollars have been lost through uncounted hours of completely unneeded meetings because it is impossible to have a subtle discussion via email these days, and that is mostly because Microsoft and Google destroyed the power of email threads.

They made the tools more user friendly without retaining most of the earlier features, thus effectively destroying one of the truly great productivity tools ever invented. Worse, I suspect the people who did this didn't even understand that they had done it.