one thing to consider is how just the optics of major players using e2e was an overall benefit.

people who otherwise would have gone their entire lives without ever hearing about encryption were exposed to the term and the marketing convinced them that encryption and privacy was a valuable thing, even if they didnt fully understand the mechanisms or why e2e might not necessarily be very effective in specific circumstances.

later, when presented between option a and option b, where one has encryption and the other doesnt, they are more likely to choose the one with it ("well, if instagram and facebook use it and say it is good...")