In the 1990s, this stuff was my bread and butter. So many great reissues and comps at the time from Easy Tempo, Beat, Plastic, Irma, Crippled Dick Hot Wax.
I remember my brother-in-law, who is also a soundtrack nut, saying, "Buy this stuff now while you can get it. It will all disappear soon." He was right.
I did start buying production music when I found that soundtrack LPs I wanted were becoming much less affordable. Several composers I liked did work in both areas. I had the sense then that production music LPs were going to go the same way price-wise, and they did (maybe to an even greater degree). Now even newly-released LPs are too expensive if you include shipping costs, so that's all worked out the way it was supposed to.