I checked on the shipping status of the replacement pipe and found out that it hadn't shipped yet.  I was told they are making the part in-house.  Reading between the lines, I think they found more off-axis threads in their stock of pipes.  While I'm waiting for the replacement, I thought I'd see if I could chase the threads with a tap and straighten them myself.  This would yield a slightly looser fit, but the pipe is not structural, so I'm not too concerned about that.

I started by making a jig to hold the pipe perfectly vertical on the drill press.  Just a vertical 'V' attached to a base, with a hole in the base for the pipe to slide through.  All scrap junky ply.

Confirming plumb with a bar of brass chucked in the drill press and ensuring it touches each leg of the 'V' evenly.  Some backlight helps make it easier to confirm a uniform gap.

Clamping the pipe securely without damaging the brass was a challenge.  I applied some grippy tape, that did a pretty good job preventing the pipe from spinning.  Not perfect, but it was enough.

I chucked the tap in the drill press, positioned the pipe carefully directly underneath, applied a little oil, applied a light downward pressure on the quill, and slowly turned the chuck by hand. 

Looks promising.  I inverted the pipe and did the same thing to the other end.

The center hole in the stave bracket needed to be drilled-out to accommodate the 1/2" pipe.   I used a forstner bit to drill a 1/2" hole in a scrap of plywood, centered the hole over the smaller bracket hole, and held it in place with some double sided tape.  Then back to the drill press to finish the hole.

The re-threaded pipe doesn't deflect nearly as much as before.  It's still a little off-center, but it doesn't take much force it into position.  I can work with that.  The lamp pipe protrudes about an inch above the bracket.

Here is the final set of wiring path parts assembled.  From the bracket up:  1/2" brass washer, a sleeve of 1/2" copper pipe (slightly taller than the protruding lamp pipe, a short threaded pipe nipple, and a threaded "washer" to press down on the collar to keep the bracket snug.  Above that is the cutaway coupler that I've shown earlier.   

The only big thing left is the shade.   I have some fabric samples from fabric-store.com  I'm waiting for my wife to get back into town so we can pick one.   Then order and wait again. 🤨