I have no issues with the OP not getting the upgrade in advance. Can't tell you how many times I needed to BUY a J fare (not D, Z or R...but J) last minute, and it wasn't available for me.

What I do have a problem is CO's policy of letting the seat go empty! If 30 minutes before flight time they know there will be no more purchasers, why NOT give it to the waitlisted upgraders? I heard a while ago the reason was to prevent people from making bogus J bookings so as to keep the seat open for their upgrades. But it seems far fetched to me. Other carriers don't see this as an issue...