Primarily for the same reason mentioned here https://news.ycombinator.com/item?id=50207846

But ultimately because if they did, everyone would flip the f*** out. It's the same reason that Google doesn't openly do it. They have former VPs of Google found new companies, or invest in new companies, that all use Google Cloud and have all juicy corporate secrets flow through Google Mail without end to end encryption but are like totally not front companies for Google.

In the mid 2010s Google was way too aggressive with trying to get data from healthcare organizations and they got told to piss off. So they made front companies where the data will flow through.

At the very top there's a bunch of dudes running around in the woods naked and something is lit on fire at the end of the festival. Like Burning Man but without the stupid hippies.