More anecdotal evidence, take it for what it is worth. (albeit not in T, so not a test case of the latest understanding)
I booked a U ORY-MAD-BOS-ORD this morning. BOS-ORD had no Z availability. I called exp, they found the IB flights, and I asked about help for the BOS-ORD.

I mentioned I heard QMAX was gone and she said well a lot of that has been stripped but they can do something if it was due to their fault or schedule change or something like that.

She didn't put me on hold but did begin frantic typying for maybe 90 seconds and said she was able to get Z BOS-ORD. When I asked how she did that, whether it was RM or QMAX or EXP Expanded Availability, she replied "I just did it."

Based on the time and amount of typing, I assume it wasn't EXP Expanded Availability. Based on Jon's latest understanding above, U/Z should be able to use QMAX to complete inventory (well it wasn't barred since it wasn't T). So, something good is still there, not sure what though.