Looking at this save game, both the one from 77 and the later one, you can see that they were quite big, took the become the crisis ascension perk and then they have been losing wars and their empire is collapsing.
The one thing I could say is potentially an issue is that they are using minerals to build ships to try and fight their war instead of using it to rebuild their dying economy, however, in reality they are getting wiped out regardless so I can't blame them for building ships either in a last attempt to survive.
Overall seems to be nothing out of the ordinary given that they are collapsing due to become the crisis perk