If 10 engineers can build 5 features in a week, then why can't 50 build 25? We easily understand why as engineers on HN, and even managers and investors understand why. But that wont stop them from trying to solve that problem. And some of them do! All of these big FANG companies are as big as they are because at some point they figured out how to solve this problem. But just like time and growth break architectures and software, they also break processes, and they eventually encounter a level where they can't solve it anymore. Then they stagnate, then they either die or solve the new problems. They have to grow to keep investors, and to grow they have to keep investors. That's why it doesn't stop at 12 dudes building an app. But sometimes it does just fine. It's really just a matter of who's investing and what returns they're looking for.