Howard Day was recently showing off all the amazing new space debris, explosions, cockpit and so on in his new WC remake project, and he caught the attention of WC1/2 designer/director Siobhan Beeman. On the subject of junk in space, she had an amazing revelation: that the developers considered an in-universe explanation for the density of everything that we encounter! In a nutshell, the same phenomenon that leads to jump points also attracts everything else, so you'll naturally see more stuff in the strategic areas that we fight over.
Heh... there's a canon explanation for that, actually. Fights take place at and around jump points, and jump points lie at the intersections of isolines of graviton flux. Debris collects to and flows along these like plastic in the ocean.
So every battle takes place in the Great Pacific Garbage Patch, essentially. :) It's the same reason our asteroid fields are so absurdly over-dense. (A WC asteroid field is roughly as dense as Saturn's rings.)