This gets to part of the problem in all these discussions. The context that the Agile Manifesto was written in was not in creating Facebook or Google, but in creating software for a defined customer who held a stake in the outcome (had invested capital, along with wanting/needing the results). Once written, something like your Google Docs replacement can get a customer stakeholder, but they won't have it at the start unless you line up early users (and even then, they probably aren't invested).
It should be clear to folks that complex technology products in past were not developed by caricature of Waterfall method that Agile peddlers show on slides. Neither today interesting engineering products are developed following some "methodology industry".