As someone working on the problem of "how do we have a hugely popular free product that doesn't make money off user data or selling information to advertisers"

As someone working on the problem of "how do we have a hugely popular free product that doesn't make money off user data or selling information to advertisers" - the reason why there used to be a bunch of free email programs and most people now use Google is that it's incredibly hard to scale free technology without doing it in a way that isn't creepy (or being acquired by a company that will eventually insist on creepiness). Hopefully not an impossible problem.