I applaud your effort, but it's going to be an uphill battle. The only two cable networks I can think of that showcase older films that appeal to cult movie fans are TCM and do a lesser degree, AMC (which used to be great before commercials).
TNT, USA networks, etc. are pretty much cable sewer systems and don't seem interested in screening anything other than lame legal shows and torturous hospital dramas. I keep hoping that these stations would quickly collapse and vanish from our cable boxes permanently.
But, we need Law and Order to be on the air, 24/7. We really do. Jerry Orbach was amazing on it, as is Sam Waterston.
But yeah, TNT will never bring back MonsterVision, although I wish they would.
Best shot of that happening is TCM, as mentioned previously.