Just a couple of thoughts, and I do understand where you come from.
If everyone only did something for the environment (recycled, carpooled, etc.) when it had a huge effect, no one would do anything. Little efforts add up.
I think most audience members do not save the programs (and I think the number of people who do is dwindling; younger theatregoers, who will before long be average-age theatregoers, are comfortable with digital everything), but throw them away (many do it immediately. I wonder how many Playbills are thrown out each week in New York - maybe that's a big number (and, before long, I think most will be gone). If they could make sure only those who really want one are given one, that would help. But people take what's offered to them. And many just want to read the bios (which I do as well, to see what I've seen someone in - but I can do that after the show). Are you willing to pay for a printed program?
It's also a cost, maybe a small one per person, but rising ticket prices are even a bigger complaint/problem than the missing programs.