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

Click HERE to view the Mullard video. This is really fascinating.....Worth a look.

quote]What is the definition of "good"? Sonic quality? Durability? Given the longevitiy of some tubes (300b comes to mind) and unless a tube fails "early," it will be hard to prove that new tubes are predictably shorter-lived compared to older ones. Or am I wrong?[/quote]

A 'good' tube sounds good and lasts a long time.

BTW, RCH Labs out of Carson City, NV appears no longer in business. 

Because the old craftsmen died 50 years ago.HELLO!!!!

☝🏻☝🏻 True enough. A lot of craftsmanship, old school tech, and perhaps now-banned materials are not available.