No interest in most old cues unless it is a szamboti or something like that for collectible value only.
IMO, the reason to own a Szamboti cue is for playing pool. If it doesn't increase in value, you at least had the privilege of playing with a great cue. Perhaps its is a broad generalization, but I think there are threads regarding most of the legendary cue makers with posters who either love or dislike the way they play. I like my Szamboti so much that nothing anybody says affects how I feel about it.
There are many great new cues being produced. I think it is tremendous that so many people have access to good equipment. I like newer technologies. But I have not found reason to switch from cues that continue to serve me well.