That's just not true. Comb filtering preserves many higher harmonics, it only removes a few harmonics while leaving most others intact. The result is a thinned out tone that is still bright. A tone knob rolls off all higher harmonics, resulting in a much darker tone. What you're describing is the reason that a pickup in the neck position sounds different than a pickup in the bridge position. That doesn't justify the idea that a humbucker has better fundamental and low harmonics reception than does a thin single coil pickup. A pickup in the neck position always sees more fundemental movement than a bridge pickup, that's not something that is specific to the pickup width.