It's all fun and games the first half hour and then the AI runs out of RU's completely, they do jack♥♥♥♥♥♥cause they've dug through all the asteroids and sent fleets of collectors to gather any remaining wreckage on the map.
Once that line has been crossed it literally does nothing, it can replenish it's fleets or create new ones and so literally just sits there, the Vagyr tend to sit at the last asteroid belt they mined and the Hiigaran tend to sit just outside of the Vagyr's firing range or in the middle of the map.

This is utterly boring obviously as it then comes down to me having to clean up the map with only fusion income to back my industry.

In 9.1 you got remunation for your rank every year, you had trade ships, fusion felt like it made more (here with 6 scavengers each with 2 fusion modules and fully upgraded fusion level I'm lucky if I can push out a battleship every 10 minutes), astroid mining was a great investement and amazing income if you protected it, finally you could build habitats, slow but reliable, I'd compare the latter to the current fusion, massive investement of resources, for a slow but reliable income.