Absolutely. And that restriction (which applies to all IFR flight) is going to severely limit the areas where you can fly IFR en route in Class G, which is why I think the discussion is mostly academic.

But the places do exist. In the Rockies, there are still areas where Class G goes to 14,500 (and higher) and the mountains only to 10K. In some sparser sections of the midwest, I don't think you'll find too many 14,500 areas but there are some "zippers" where Class G gets pretty high relative to the terrain and some pretty empty flat spots in parts of the midwest where you can get that required 1000 over the highest terrain.