I have tried to get Uranometria (listed as "temporarily out of stock" for quite a while now, which I think is a euphemism for no longer in print). I tried to get ahold of them to ask when it would be available and there was no response.
I think (and I definitely HOPE) that is not the case. I doubt they sold all the inventory they bought when they took over operations. I have bought 7 books ever since and all of them have been out of stock, sometimes for a while. The second part of your sentence, actually explains things. I do not believe books are what they ran out of, people (and oversight) most likely is. It must be a thankless job as the turnover is quite impressive.
I hope sooner or later someone takes a trip to the storage unit(s) in Richmond and finds a box of Uranometrias as I am patiently waiting myself.
I so wish things had gone differently and the inventory had been bought by one of the merchants we buy equipment from. Most likely, no one wanted to take over a very big bite to chew. We can only hope.