Well, in these kind of setting, Earls are usually the lowest limit for "real" nobilities.
Viscount and Baron are treated as closer to commoners.
In stories that try to put it in good way, lower ranked nobilities are pictured as being further from politics, scheming, and formality, so they can still act with commoners' sensibilities. But they still enjoy the life standard as nobility (such as no working your arse since young age).
Or in the story that put it in bad way, lack proper education, unrefined manner, clueless about the social rules, and worst is acting like new-money who never tasted status so they flaunt it indiscriminately.