Facebook won already in like 2012 or something. What was before that - MySpace? - it just sucked compared to Facebook. Terrible UI. Completely useless, siloed without the "real name" policy.
Facebook was a genuine innovation, both in terms of UI, and in terms of marketing (targeting elite schools first was genius, but hardly non-competitive, anyone could have done it).
Facebook pays teens to download VPN to measure app usage on a users device: https://techcrunch.com/2019/01/29/facebook-project-atlas/
Facebook backdoor testing after their VPN was removed from the app store: https://9to5mac.com/2019/01/30/facebook-research/