Nope, you summed it up well enough. But I have stuff to add, anyway!
The tweet probably refers to the Art of Play's inventory of the old USPC stock running low. They are a playing card retailer, after all. (Well, they're Dan and Dave disguised as a playing card retailer, if you want to boil it down to brass tacks!)
The early stock released in Erlanger was considered inferior. I have a newish theory as to why - they had to comply with a new Federal regulation regarding the materials they used to make cards, the short version of which being that they had to remove petrochemicals from the manufacturing process and use more post-consumer recycled content in their paper. The Bicycle Eco edition was probably the first of this lot - they switched to vegetable dye-based inks and starch-based coatings. It was a little while before they managed to work out the kinks - the development of Magic Finish coating helped a lot.
By 2011, the problems were worked out and much of what they produce today is (or at least has the capacity to be) of better quality than Cincinnati-made products from near the end of that factory's lifespan, the major exception being that they appear to have switched to a lighter-weight stock for mass-produced Bicycles, from 325 gsm to 300 gsm. But they no longer measure their stocks in gsm anyway...
The biggest issue the factory faces today is their own quality control standards - they're capable of great work, but they often seems to let inferior work slip by and try to pass it off as acceptable. One of the worst issues people run into with new USPC decks often is poor alignment, between the faces and backs as well as between the backs and the cutting die. Magicians can really use it to their advantage, but most card players and collectors find it aggravating, especially as thin borders have become fashionable.