What exactly do visible ply- and cardboard have to do with ST II? They were re-using a 7-figure bridge set, a 6-figure hero miniature -- leveraging off the leftovers from a 40mil plus movie.
And as far as that goes, doing the worn 'junk ship' approach is the cheap and easy way to do spaceships, both inside and out. That's why amateur films leveraged more off the SW/ALIEN look than the 2001 look -- it is achievable through creative scavenging.
It has to do with the fact that they didn't use CGI in that time; the technology wasn't available yet, or it wasn't cheap enough. If you need a set to look accurately weathered, you need to let it sit for a long time, or apply CGI. Just look at BSG's sets; in the first season, they were hardly weathered at all, it was only in the last season that the sets really came to life. I doubt either could have happened on STII.
Of course, you could always apply weathering the old fashioned way, but as far as I know, that's very time consuming to get it right.