"Data privacy is biggest challenge of our time. Your personal data like email is owned by service provider and that data is used for things like ads you don't want."
Not everyone uses Gmail. I use Fastmail for my e-mail, and they neither show me ads nor read my e-mail. (They charge a modest fee for the service instead.) And as far as I know, they don't claim to own my e-mail.
"Imagine UPS, USPS, FedEx etc reading your mails to send you ads and keeping your mails with them? Sound bizarre, right? It is to us."
It is to me too. That's why I've never used Gmail (or other ad-supported web mail providers). And I use Thunderbird to download e-mails to my machine, so my messages don't stay on Fastmail's servers if I don't want them to. (I trust them to not keep copies of my e-mails forever after I delete them, and they have little incentive to do so.)