I'm not convinced they're visiting us. None of the reports I've seen appear credible. But non-interference is often critical to scientific study. They could just be doing a decent job at hiding from us.

If they're out there, I'd be shocked if they wouldn't visit. Our solar system has been showing life signs for 3.5B years, and technological signs for about a century or so. There aren't apparently many planets like ours around. We are a very tempting target for study.

It appears to be quite difficult to develop a spacefarring civilization. But there are credible models for sailing light beamed from stars, and even gravity surfing orbiting black hole pairs. The vast energies required for interstellar travel should be impossible to conceal. We ought to already be able to see them out there, if they're close.

13.5B years is an eyeblink in the potential age of the Universe. We developed early. Perhaps not first, but very early. Intelligence and technology are difficult and expensive to develop. Our hubris may destroy us. We might easily be alone in our local neighborhood. Technological civilizations may still be rare. But once they go interplanetary, there are few ways for such a civilization to go extinct.

I'm fairly confident they're out there somewhere. I'm sceptical that they're close. We may be the first in our galaxy, or even the Local Group. Who can say? I don't know.