35mm has gotten so expensive to process, it's pushing more holdouts into digital. Even my 71 year old mom is sick of developing costs, and is buying a digital. So that takes care of the consumer market, which is now 99.9% digital.
Many pro-sumers of the past have also now gone digital. When I walk around with a Leica or Canon, they come up to talk. It's always, "I used to shoot one of those....15, 20, 30 years ago..."
Finally, we're left with the avant guarde, who like mechanical marvels, or just being different. And the speculators, who believe things like these are investments. And those are very few in numbers.
I've never been able to sell much 35mm here, and barely on Ebay. There just aren't that many people interested. Supply and demand is at work.