I remember reading a novel set in a solar system that had a very rich asteroid system, significant resources at the gas giant Trojans, and no habitable planet.
It had had a very rich civilization until interstellar trade collapsed, but since isolation, lacking the resource depth that a habitable planet would have provided, had become a very dismal place.
Ideas?
Not a lot to go on, but what is given matches Joan D. Vinge's "The Outcasts of Heaven Belt".
Ticks the boxes of asteroid-belt only system & economic collapse.
The most memorable thing about it to me was the metric time scale. Perhaps you remember that as well.
The Heaven system had been colonized because of it’s resource rich icy and rocky asteroids and planetoids, and the moons orbiting its gas giants.
From the summary here:https://littleredreviewer.wordpress.com/2014/01/16/the-outcasts-of-heaven-belt-by-joan-d-vinge/
