Would you buy a tube amp if you were unable to use vintage tubes in it ?

It would be interesting for me to compare my VAC Avatar SE full of vintage Mullard and RCA tubes with later VAC integrated full of Chinese/Russian tubes.

"new tubes are better than no tubes". This is something that would be very hard to argue with. I certainly won't. Yes, modern amps should sound good with whatever new tubes are available, but..even Kevin of VAC himself recommended vintage tubes for driver and power output tubes. Surprisingly to me he suggested  I stay with selected Chinese 12AX7 for preamp. I of course did not, though I am sure he knows what he talks about. Besides the sound quality I also want reliability and longevity.

Why would you not be able to use vintage tubes??

Has the Thread Initiator ever heard any vintage tubes?

Absolutely.  I’ve run precious few NOS or vintage tubes in my amps/preamp over the years.  Tung Sol, Gold Lion, and some EH and new issue Mullards have been sounding darn good to me.  Even the modern tubes that I haven’t "loved" have been pretty pleasant.

It's difficult for manufacturers to supply reliable consistent vintage tubes in large quantities, so many world class amps source tubes from Russia or China, or wherever else new tubes are made.