... Let's recap, shall we?
Humans entered this galaxy three millenia ago. In that time, they have not managed to:
Join the local alliance of intelligent species
Reverse-engineer the "energy barrier" that aliens use instead of airlocks
Terraform more than one planet
Establish an artificial ecosystem on a space station
Improve their air recyclers, or otherwise provide any treatment for the Space Asthma that gives its sufferers a life expectancy of 35 years
(Mind, I don't think the energy barrier thing is the best idea - what happens when you have a power outage? - but it's nonetheless something they specifically covet.)
There also doesn't seem to be any equivalent of cell phones or credit cards, no significant robots except for security drones, no ftl communications... all they've got is universal translators and starships that don't seem to need any kind of fuel.











