With the ongoing and high interest in vacuum tubes for musicians, audiophiles, vintage audio and radio equipment, etc, the prices might rise to the point where it become feasible to restart manufacturing them in any country including the USA.
There is no doubt at all that my PP 6V6 monoblocks sound different than my Marantz super linear amp. Different, not worse. Distortion on my Yamaha solid state amp just isn't the same as the 6L6 Traynor. Different, not better. It's a matter of taste. And then there is repairability... did you ever try to find power transistors or power IC's for repair? Good luck on that... it's usually much harder (and sometimes more expensive) than finding tubes... even now.
I sigh when I hear or read people biased against something as old technology therefore it must be inferior. Being newer does not necessarily mean better, nowadays it often just means cheaper.
The Triode was prototyped in 1906, the germanium point contact transistor was prototyped 21 years later in Bell labs. Transistors started out being more expensive than tubes in the 1950's but eventually got cheaper by the 1960's. A lot of new technology breakthroughs were going on in those decades but it might be concluded that making tubes is easier than making transistors, so it's just a matter of time before the economics of tube-making makes a good business case in more countries, and more tube factories spring up. I sure hope so....
73, Ed
PS: speaking of business cases, the Shuguang tube factory eventually closed because a real-estate developer wanted to buy the land. There is a lot of money to be made when something is scarce (in this case, land) but the demand is strong.