Because IMO too many guys go chasing after certain NOS because they were told to go after it, not because they can actually hear any difference...seen this happen in listening tests. And besides, those types are driving the supplies down and prices up by using up the things they are told to buy (again, not always the best for the job). In some circuits a cheap Sovtek works amazingly well. Most modern guitar amps were designed especially to work well with available new tubes, not NOS. But snobbery often takes over and denies it.

It's not consistent snobbery either. I've seen two "experts" argue about which EF86 is the best, almost to the point of violence. There have been endless wars on rec.audio.tubes and alt.guitar.amps started over which obscure hard-to-find 12AX7 one should pay inflated prices for....that's the worst part, when you have egomaniacs telling people what to buy. And disagreeing. Again, this is so much like the wine-tasting "business" that it's depressing to me. Or like the childish wars people get into over role-playing games.

>BTW does anyone really take Tellig seriously?

You'd be really surprised. He has a huge fan following. I have met otherwise reasonably intelligent, well-educated men who talk about Tellig the way some teenage girls talk about Justin Timberlake. And some of the stuff he raves about is just crap IMO. Again, lack of critical thinking is how this crap starts. We end up with $50,000 speakers that are awful sounding, being built up into big sellers. (And once-common WWII 6SN7s selling for $250, almost overnight.)