It’s a hard question, and an interesting one, too. I feel like anything I say, that attempts to be serious, sounds really pretentious, but I do think it has something to do with the more distinctive English identity of Small Faces with very English cultural references? Maybe? Entirely different music, but a bit like Blur, who never really caught fire in the USA.
Frampton in United States was a little more at least at first, of a kind of teen idol, but a little more mystical and deep, somehow. The lyrics aren’t exactly Chaucer.