I wonder if the "appeal" of gonzo is because everything "normal" has already been done in RPGs, specifically in D&D's 40 year history.
More than once I've been brainstorming new campaigns only to discover my "gamma world with wizards" is darksun. Or the "fantasy pirate/merchants on steam train" is too close to Eberon Lighting rails.
Smaller scale examples; create some hillbilly dwarves everyone thinks of gully dwarves. Anything drow is dual-wielding scimitars and spiders. Describe two features of creature and two or three players name it and rattle off its attributes.
There are only so many ideas (well infinite but most the normal ones are similar enough to be same, the rest are gonzo). The large published worlds Birthright, Eberron, DL, DS, FR, Greyhawk, Mystara, Planescape, Ravenloft have done a lot of them. Even some gonzo, cough, Spelljammer, cough.
This is worse in rules heavy games (such as Pathfinder) where there are clearly delineated abilities, powers, conditions, threat levels and pre-determined countermeasures. You can't even get very gonzo and stay within RAW. In old school games it's easy to gonzo overboard. It becomes silly and in away, also destroys suspense, tension, surprise, wonder. When every day is "sasquatch wizards riding dinosaurs with laser beams" it all becomes mundane.
In the end I'm just bemoaning the fact that I'm in a wasteful arms race of "new" with "seen it all", jaded players.