But those individual adventurers are part of that people right? Halfling wizards, clerics, druids, bards, and warlocks exist right?
So... humans built a kingdom and they have a church with clerics who worship a god, and they have a holy relic that is targeted by some group.... but halflings have a village, with a church, with clerics who worship a god... and they aren't worth considering or even caring about?
Driz'zt and his companions, many current leaders in the Sword Coast, multiple villains... all of these people are "individual adventurers" they are certainly worth noticing, but a halfling adventurer showing up to stop an evil ritual, or to fight against an army is totally unexpected because.... why? They clearly exist, they clearly do that thing, halflings clearly have magical classes and rogues and all these puzzle pieces that makes everyone else worthy of being paid attention, but they are ignored because they don't do anything and are nothing but simple folk who lead simple lives? You can't be both a race that provides a ton of badass adventurers and be a race of people who never do anything important or get involved in all these plots and issues that adventurers get involved in.