Probably a large majority of people who ride any kind of mountainous stuff. In my area, we've got plenty of gravel climbs that average 12% or more over a mile at a time. And check out this gorgeous road that one of my friends recently found:



I suppose "need" is a strong word, but if it's a question of what's optimal, I actually think that most road bikes in hilly areas should come with ratios of 1:1 or lower, whether intended for gravel or otherwise. Even in the paved lowlands around here, I see tons of people badly bottomed out on their gearing during climbs, and people avoiding very fun roads simply because the gradients get steep. That's awful.
Ideally, common chainring combinations would span a much wider range than they currently do. From what I can tell, a majority of people on road bikes have very little use for the top-end on modern road bikes. For the weaker riders, a 42-26 or even 40-24 would offer adequate top-end in a 1x-plus-granny scheme, while permitting a comfortably tight-spaced cassette.