...I can't decide about the rest of the world, but we been building and riding gravel bikes (not gravel racers) here in NorCal since at least the 80's. The original MTB's were essentially reworked Schwinn paperboy bikes that were designed to take advantage of all the unpaved roads and fire roads we have here.
And almost all the levee top roads down in the Delta region are unpaved gravel.
So that's a whole lot of roads that go through some nice places, all of which are denied to you as a cyclist if you are unable or unwilling to put together something that will carry you on those surfaces. Here is my recently repainted and reworked Raleigh Sports, which I originally put together as a go anywhere, carry a lot sort of bike. It does fine on gravel, as you would expect, but I don't ride it very fast on gravel, because that's a good way to eat some of it.
