I understand your frustration. I cannot count the number of unfruitful exchanges I've experienced. Forum discussions all-too-often descend into a skeet shoot wherein an idea is advanced only to be shot down quickly. I remember feeling so battle-fatigued in one forum that I simply disengaged and determined to never again subject myself to such misery.
You raise some good points about prophecies that are ostensibly unfulfilled. I can only say that there are times when Preterists, Historicists, and Futurists must declare: "I don't know!" Because I am shortsighted (literally, I can see only objects that are close by!) my lenses help my eyes transcend their limitations--to a point. But my vision is not telescopic. It is limited, even with corrective lenses. And so it is with Preterism (bible prophecy was fulfilled in the past), Historicism (bible prophecy was fulfilled throughout recorded history), and Futurism (bible prophecy has yet to be fulfilled).
My fear is that the meaning-making optics we bring to Bible study all-too-often become ideological, meaning that our perspective becomes self-evidently true and morally justifiable. The Bible then becomes a lamp that is rubbed and the hermeneutic genie appears. Only, the genie's wish becomes my command. The Bible becomes a tool of control.
So let me simply repeat, "I don't know" what Zechariah or Ezekiel had in mind when they spoke about re-built temples, scattered Israelites, and such. I can only say that what I "see" with my hermeneutic (interpretive) lenses makes sense--to me. But my so-called "lenses" are still very limited, historically, linguistically, and culturally, in regards to the ancient Hebrew world. So, there it is.
Bye for now!