There is a TON of great classic rock to enjoy that never sees airplay and the reason is the researched tunes have "known" demographics that can be sold.
One, you're quite right about classic rock having a lot of deep cuts that just don't make it outside of some specific instances. On the other hand, not only was new wave not entirely congruent to the 1980s, but a lot of what gets called new wave on various stations is only music that existed in the 1980s, rather than being actual new wave. New wave was fairly tight and the rest is padding.
"Darkjazz" really came and went, and it's unfortunate. I'm still working my way through it but there was a hell of a drop-off.
Speaking of researched tracks, I think when an artist dies, there's a contraction of what of their tracks get played on air.
Another thought, this one purely math. If you bought, say, ten CDs every year, new releases, well, the average age of your collection will age at about half your own age rate. The only ways to prevent that, if this concerns you, is to either jettison your old music or gather ever-increasing amounts of new music.
All of this is to say that, unless your preference is "whatever is on the radio ... played a reasonable volume" (Pictures for Sad Children), you're swimming upstream, against the fantastically evolved. Taste gave way to faddishness, then payola, and now, well, The Algorithm. It's a fight to find what you might like rather than what is just being extruded like soft serve.
I had expected that some of Badalamenti's stuff would have opened up since his death, like his score for Witch Hunt, but no luck. His stuff was sort of a wellspring, among others, which intermingled into that little creek we called darkjazz, for a while.
I originally got into it as a primary component of a long set of mixes for a particular mood, namely that I would have instrumentals (primarily darkjazz) buffering slow tempo "torchy" kinds of songs (Mel Torme, Julie London, Nat King Cole, Billie Holiday) and the "once every ninety minutes" track which was a little newer. The idea being that the darkjazz doesn't call too much attention to itself and keeps the mood going.
In another comment, I said it helps to be around others seeking new tunes. It helps a lot! Their bias into our system can bend things back into a fairly normal curve. It is like rolling back the clock on our music age.
Right now, I am living that with people at their music seeking peak. Super fun and very invigorating.
Recommended.