I think to address this part of the issue is that most companies that are in the diesel community that actually produce parts are very small companies smaller than you might think. I think elite is 5-7 employees, MPD is probably about the same, Rudy's is probably 10 or so ect ect. This goes for the same in the duramax and Cummings world as well. You don't have the holly, edlebrocks, morroso ect ect backing them up with big money and the ability to mass produce product easily. As far as I know almost all shops are several weeks out, parts in some cases like turbos are a couple weeks out ect.
I'm not saying what going on here is any of these things, but I think that's why everyone finds these issues present in the diesel community, almost all companies depend on other places, machine shops ect to get things done. so some of it is out of their hands. Sucks really because the end user is the one who suffers