Hopefully I can clarify a few things for you Eye. The new ACE Jackets, other ACE kit, and almost all new shiny kit systems are issued and exchanged by attrition to prevent the mad stampede at the clothing counter. The size of jacket that you wear, 7348, isn't a common size, but isn't uncommon either.
The thing to realize with attrition is that it affects all levels of supply, and not just your local base supply. For example if the Supply Depot is holding 200 legacy jackets of that size and 500 ACE Jackets of that size, the Depot will ship out all the legacy items first. After that is exhausted, they will ship out the ACE Jackets. Then the Warehouse at the base level has to exhaust their supply of legacy before moving onto the new kit.
There is also another force at play here that is probably a little more pertinent to your situation. All these jackets/bib overalls/flightsuits are being made by the same manufacturer, for all the colours(OD, CADPAT TW, CADPAT AR), in all the sizes. This presents a unique situation with such a large order as there needs to be extended lead times because they aren't exactly allowed to be running a sweatshop, and no one would bid if the timeline were too tight. Typically when a new clothing system of this magnitude is issued, the intent is to get everyone into one jacket. After this is accomplished then we can start backfilling for exchange stock at the local bases starting with the most popular sizes. I guess the point I'm trying to make is that there is a lot more going on behind the scenes that isn't just a supply manager acting like an @$$.
On the plus side the flight suit roll out is moving along at a pretty good clip. N2M the ACE Jacket's collar sucks(make sure to grab a neck gaiter at the same time)
Hope this helps, FYI your size has less than 75 jackets available for issue forces wide, so don't feel singled out.
P.S. Hopefully I'll see you in the AESOp Trade! Still waiting for my AVOTP to come through.