I was one of the early subscribers of Opps Daily! I loved the idea originally when it came up but after a while, the daily emails got a bit much. I believe I suggested a weekly version/aggregate over a daily email (which you immediately implemented).
Watching it from the outside, I'd say after a while it became "the ideas are decent/worth looking into, but I already have too much on my plate right now that I can't pursue any of it" and the aspiration to follow through is pretty much gone. I think monetizing based on that (and making it worth the time investment) is the big egg we all want to crack.
Anyways props for you for running it for so long! I saw the email and appreciate you taking us on your journey through the lifecycle of it.