Well, the main thing is, Gelbin has, to my knowledge, the widest breadth of inventions that have meaningfully advanced gnomish society as well as the advancement of technology in general, which are two of the major criteria in the gnomes' meritocracy. He's credited with inventing the mechanostriders, which revolutionized several industries, the Deeprun Tram, which opened up unprecedented access between Ironforge and Stormwind City, and--if I recall--the mechsuits and gunships used by the Alliance. It's hard to compete with that Tony Stark level of ingenuity and drive.
I mean, yeah. In the real world, world leaders meet up and form interpersonal relationships all the time, man, have you paid no attention to world politics in the last 2,000 years?
I'm sorry you don't understand how interpersonal relationships form an integral core of diplomacy, but I suppose the beginning of March 2021 is as good a time as ever to learn this.