They don’t like us and are deliberately hiding from us.
Yes, but he’d be able to look at skyscrapers, Panamax supertankers, freeways, M1 Abrams tanks, the millions of acres of corn in the Midwest, supermarkets, and crowds of millions of people with straight teeth and backs, and get some idea of the power and wealth of the modern world.
Of course, it’s possible that we’re observing the effects of these god-like civilizations, but we think they’re natural phenomenon. Maybe that’s what quasars are. Or dark matter could be due to millions of Dyson shells around most stars in the galaxy.
But a computer is actually more advanced than a skyscraper. An ancient Roman could understand how impressive a skyscraper is because it’s a manifestation of his own ancient technology. He can’t understand how impressive a computer is because it has nothing to do with his ancient world.
And that’s my point. The more godlike some being is, the less non-godlike beings like us could understand them. The things that would look most impressive to us would probably be the things that are least impressive to the godlike beings.
As the godlike beings move up the scale, they would abandon more and more of what, to them, are remnants of ancient ways. But we wouldn’t be able to perceive this as an advance because we can’t understand the most advanced aspects of their culture. It would look like they were losing what, to us, appears as high technology and we’d think they were falling into a decline.
Perhaps they all withdrew into cyberspace because the real physical world is both highly limited and mostly dead matter. Or perhaps no intelligent species ever survives high technology for long. Or perhaps they are just very far away. Or perhaps it simply isn’t worth it to spread far from the home star system, given the speed of light limit. Or perhaps sufficiently advanced species normally become so interconnected that they become some variety of group mind, and they don’t want to travel far from their home world because it’s like having a lobotomy.
All sorts of possibilities.