Do you really believe people use gmail because of its brand?

I don't know about any security brochure, but I know I can setup 2FA to use push notifications (not an insecure SMS number), and can check where all of my logins are from, and have "suspicious" logins blocked automatically, etc, etc. I can also create single-use passwords for insecure devices (such as a youtube password just for my apple TV). Not to mention how amazing they are about spam detection.

I think their security posture is actually excellent.