I think that it's important to distinguish between your average UFO sighting and visitation from a god. Even taking your premise as a given, it's a fact that many UFO sightings turn out to be nothing but a hoax or something boring and mundane, and there's no reason to assume that we caught them all. Once you eliminate a reasonable number in that way even if you assume that all the rest are these gods you don't have the same QUALITY of incident.
They aren't talking to us, they aren't performing miracles, they aren't founding religions - other than a few pathetic cults. We don't get to see them building monuments or raising the dead or smiting people. It's clearly a whole different - and way more boring - kind of encounter. If you can even call it an encounter at all!
If we want to return to a point where we have some real attention from the gods, we need to look at the differences. We don't have the full picture so this is hard, but I think my plan of getting rid of civilization and technology as we know it is a solid one. Serious, high-quality sightings of gods have declined consistently as technology has increased. We need to eliminate electricity, we need to clear the air of radio waves and other signals, and we need to stop using fancy manufacturing techniques.
Once we're back to the Bronze age or less, we can look at the situation and re-assess if needed.