I would suggest you are perhaps making the wrong analogy in this case.
Of course we can't get all other humans to listen to us, because there is only one human species in real life-- which is very different than within D&D. In D&D there are dozens upon dozens of different species, meaning that you would only get to get things done with a small subset of all those sentient people.
So the analogy is more like if you were a member of some group within humanity-- occupational, racial, national, gendered, religious, or any other subset... and more often than not someone within that group would give you information or assistance when asked. If you were a member of the Teamsters Union and you found another member of the Teamster's Union and asked them to give you a hand with something (especially when directly related to Teamster activities)... why would the DM even give us the chance that your Teamster friend would say 'No' on some of the most innocuous things by having the roll possibly fail, and thus cutting off the advancement of the story? There are hundreds of thousands of other NPCs out there who all have legitimate reasons to tell that PC 'No' on their request for assistance... why give this fellow member of some connective group the chance to do that too? What's the point of being a Teamster if you can't be assured that more often than not, fellow Teamsters are going to help you out?
***
I do want it to be said though that this idea that I was just coming up with off the top of my head at the time was not meant to be universal across the entire game-- never having the players "fail". This was specifically asked of me as what I'd do for species mechanics and given the specific suggestion of elves interacting with other elves. And to be fair, I'm not even saying that this idea that elves will almost always help other elves in most regular interactions is in fact the right or best idea... but merely that this idea I feel is miles better that the piddling 4 game mechanics the game currently uses to distinguish one species from another.
People have been saying they need ways to distinguish a species as being substantively different than the other species, and apparently believe that letting Halfling re-roll 1s and Dwarves resist poison does the trick. I mean, if that's all they need then okay... they can be happy with what the game presents and use it to their heart's content. For me personally, though, I don't find those "game mechanics" meaningful in any way. So usually when I'm DMing I just see who these PCs are and what they've done and then let them do the stuff they are looking to do based upon that status-- and not bothering to use mechanics to first check if it "works" or not. Because to me... a failed check is the "No" to improv's "Yes, And..." It stops the story in its tracks. Which occasionally is fine... especially when we're talking about really, really important events that might require a lot of effort to succeed on-- roadblocks can create drama and drama makes eventual success have more meaning... but for most rudimentary action that the PCs do? Keep the game moving. Advance the story. Let who they are and what they've done actual be meaningful. Because forcing them to use mechanics for no good reason other than "It's a game!!!" defeats the purpose of us playing an RPG rather than a board game.
Of course, this is just my opinion... I could be wrong.