I think you're underestimating how difficult operating at that scale is. There's no "just" here. It's hundreds of millions of people, all over the world, using

I think you're underestimating how difficult operating at that scale is. There's no "just" here. It's hundreds of millions of people, all over the world, using your app 24/7, with the expectation that your platform is always there, that it shows consistent data and that it responds instantly. That's very difficult to build and maintain.