atmosphere--- Let's slow down here and try to work together. I could have expressed myself better on some points, so...
On tubes vs. solid state specifications: Yes, all active devices do have variances, and, having built numerous of my own preamps, power amplifiers, voltage regulated supplies, and unity gain buffers, I'm well aware of those pesky variables. But there's a critical distinction between electron tubes and solid state devices. The classic tube manufacturers (RCA/GE/Sylvania/Tung-Sol/Raytheon/Mullard/Amperex/Telefunken, et al) did not ever test or deliver their products with absolute min/max control limits. Instead, they simply stated "typical" performance criteria. Check any receiving-type tube data sheet, and you will see that no guaranteed min/max performance control is applied, other than for the usual destructive ("do not exceed") limitations.
Solid-state devices are entirely different---there are lots of guaranteed min/max limits provided for many operating parameters, and they're all listed on the related data sheet. So, in comparison, there is really an important difference between the way tubes and solid-state devices are made---and sold. Tubes come with uncontrolled performance variables, whereas solid-state devices vary, but only within specified limits. That's a real distinction.
Regarding audio products using vacuum tubes: Yes, there are now many small companies making products that use tubes. In the '50s and '60s there were many LARGE and small companies making products with tubes. Solid-state never got traction until the mid-70s. And the small companies of today that supply tube audio products import virtually all of the tubes that they need.
Re. the guitar market, yes, agreed. It represents the dominant demand for receiving type vacuum tubes. The audiophile market alone would probably be insufficient to justify viable vacuum tube business. Of course, the guitar + audiophile market in sum is just a tiny blip in the overall sphere of consumer electronics, so we'll never see the return of the big corporate tube producers like those that I reference above.
Re. domestic tube manufacturing: Hey, right! Welcome to RCH Labs. Hope that they do well! They started up in late 2016 and they're making 6L6 output tubes. Looks dicey to me. Korg doesn't actually make any conventional receiving tubes, just some experimental nuvistors, an extension of the old RCA technology. The Western Electric tube facility is actually in Kansas City rather than GA; the latter is corporate home. My information is that there is no true commercial production ongoing at this time. I could be wrong.
