Why aren't new vacuum tubes as good as old ones?

I'm encouraged by the sonics of many current production tubes, especially some coming out of China. Many rank right up there with the legendary tubes, though more often than not, the old American and European variants still hold the edge in absolute terms. From my experience, I think it's in ruggedness that the old tubes hold a big advantage, particularly over many current production European tubes.

Shuguang tubes possess the best reliability in the industry reliability over the past decade. While the premium Chinese products get most of the attention, the run of the mill Shuguang 12AX7B, EL34B, KT88, and 5AR4 offer surprising sound on top of that reliability. Speaking of surprising, the dirt cheap NOS military Shuguang metal base 6SN7 (labeled 6N8P) will as well.

Personally, I find buying old used tubes that most pass over in favor of spending a lot more for NOS finds on sites like ebay to offer tremendous sonics, longevity, and overall value.

Lost art. That's why. New stuff can be very good, but will always be different. I wish some of these way-to-damn-rich philanthropists would occasionally pick a dying (beautiful) technology to keep alive (like vacuum tubes back in the 60's-70's) -- rather than the trendy shlock they typically flock to -- in order for future generations to rediscover some of the beauty and knowledge that has been created by our predecessors.

A lotta folks think all tubes sound the same, or essentially the same. Wouldn't vendors selling new tubes be inclined to market their product as being superior to NOS tubes, just like the NOS tube vendors, you know, for the profit to be made? Gosh.....another audiophile debate in progress. As for myself, I'll stick with WWII tubes from Sylvania and Tung Sol. Y'all can divvy up the new stuff. :-)

Thanks for the info Atmasphere.

What price glory? My NOS tubes (two 6SN7GT and a Tung Sol 5u4g rectifier) along with tube dampers set me back as much as the headphone amp. Is that wrong?