The main reason why years advance slowly is because we are in between two specific events in the Artemis official canon (check out the game handbook for a full timeline). We kind of have to suspend belief, or we could say it works on a different cycles.
A year is very ‘Earth’ based as it is the time it takes our little planet to go round the sun. When you consider that Earth is not the only planet in the galaxy, and there are multiple USFP alien races, it could be concievable that we work on a different measure for a year.
Persoanlly, I simply suspend belief on this matter. Time and distance are both ubitsnof measure that have to be ‘abstract’ in Artemis. It is one of the reasons why I designed the stardate format as I did,to create ambiguity when it came to scales of time.