You've never worked at a large enterprise, have you? You'll at most interact with people in your direct product group, which are likely well below 100 people. IME often even below 50.

You're delusional if you think that the people being in the same building changed that whatsoever. And especially if you think that connections across buildings randomly happened without a specific goal.

Sure, you see them in the hallway or in the street, might even nod into their direction if you're feeling particularly social that day... But that's it. And people working in different cities might as well be separate companies.