> what would have happened if Mark Zuckerberg saw the failures of other social networks and "learned from experience" and didn't create Facebook?

The world would be a much better place.

https://en.wikipedia.org/wiki/Criticism_of_Facebook

Even setting that aside, your premise doesn’t make sense: you can’t “learn from experience” by watching others. The whole point of the phrase is that you have to do it yourself to learn.