I think it's hard to argue (although some people clearly did) that making a search engine is easy. You need to index all of Internet, cache it maybe too, rank stuff, filter out spam, work over different languages, do something about images, parse a lot of (broken) HTML, maybe run some js to figure out what a dynamic page should show, then serve it up super quickly... google is faster than pinging a local (!) NFS server at my work.
But then I remember a comparison on HN about how booking.com is O(50) people and Airbnb is O(2000) total. Or I remember the total headcounts at Twitter, an app that lets you post very short messages.
Or LinkedIn, a vast company with a very subpar UX, basically an inferior clone of a dozen of other social networking sites, only kept afloat by its network/monopoly effect. I mean, searching for people by name barely works! You're better off using Google to look for people on LI that its own search box!
No doubt it's just my cognitive limitation, like I can't visualize the vastness of the Cosmos, but this is a close second.