Heh. In another Star Trek thread, I fan wanked thusly:
Here you have the Humans, fresh out of World War III/Eugenics Wars, with who knows how many cities dying in nuclear fire. (Spock says 600 million dead in a TOS episode.)
In the movie “First Contact”, we see a leading astro-theoretical-physicist [Zephram Cochrane] and his Chief Engineer (Lily) seeming to live in what appears to be run down conditions, dressed in raggety clothes, implying that poverty and “want” still exist. They think the Borg attack was someones [another human faction] attack satellite, implying that the fear of war was still not far from their minds.
FTL drive becomes a provable and practical fact, and suddenly the Humans are thrust into a much bigger stage. This may have had an effect of a species wide “epiphany moment”.
I think human condition improves drastically (possibly aided by contact with Vulcans) within a generation, invigorated by a new hope for the future, and by the wonder and challenge of exploring deep space in person.
The Vulcans (and the Tellerites and Andorians) have been in space for centuries by this point.
Maybe the Human’s enthusiasm was infectious (as viewed by the Andorians), or maybe they thought it was quaint (as viewed by the Vulcans).
But anywho, the Humans go exploring bumping into things, learning on the job.
Bumping into other star faring species, and getting into short conflicts with them. Conflict with the Romulans and Klingons are specifically mentioned in various points in film/TV episodes. The role the Vulcans/Andorians/Tellerites in these wars is not explained. It’s entirely possible the older species stayed out of the fighting, at least at first.
The TV series “Enterprise” implies that the threat of hostile interstellar species (the Xindi and the Romulans) may lead to greater wars, especially if each planet is picked off one by one. Also, in the series, we see that the various worlds learn that they can indeed cooperate to some extent with each other. So, the Humans suggest some kind of Interstellar Galactic Alliance. The Vulcans suggest a more… restrained name for the cooperative union.
It’s possible that the older Founding Member species were more than happy to let the plucky and idealistic Humans take the brunt of the [del]casualties[/del] danger (while exploring and fighting wars) as part of this new “StarFleet”, since the Humans seemed so eager to do so.