I mean the statue over the pit looked exactly like it's bubblebath spikey haired humanoid manifestation, right next to which is what looks like an anthropomorphic terror dog statue, plus of course an
actual terror dog is seen running around. All signs do indeed point to the third coming of Gozer (or fourth if the video game is still on the table, canon wise.)
My assumption thus far is that Shandor and his cult didn't limit their activities to Manhattan, that they also had some other site out in this nowhere town (I'm assuming mid-west, but I guess upstate New York isn't totally out of the question?) Maybe this was the first attempt at a gateway but there wasn't enough people around to focus the spiritual turbulence, or it was a second attempt after the central park west antenna failed to open, but Shandor died from a botched surgical experiment before the cult could complete the ritual and it was left abandoned. Fast forward 100 years and it's finally charged up to the point the New York gate was 40 years ago.
It's a working theory of course.