> In exchange for free mails, would you let your postman open your letters, read them, and insert ads related to their contents?
Note that this is not the case anymore: https://www.nytimes.com/2017/06/23/technology/gmail-ads.html
We never did that for G Suite, but with this announcement we also stopped doing it for consumer.
Disclaimer: Googler working on Gmail. Please stay :-)