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

I run a combo of NOS vintage tubes and new reissue tubes. It depends on where and how they are in the circuit. Personally, i think that in many cases, one gets possibly a more reliable tube with some of the reissues. Simply because the NOS tubes, like the 50's and 60's tele's etc are really unknown as to their usage. I can't say how many times i have bought NOS 'vintage' tubes only to look at the tube pins and to know that this tube is more than just used. Do NOS vintage tubes sound better than the current reissues? In most cases, i would say they do, but again, depending on where in the circuit. 

Today, I also think that some of the new power tubes are superior to the power tubes of yesterday, certainly in SQ, maybe also in reliability. ( although that depends greatly from tube to tube). 

Would I discount a good piece of tube gear if I could not use a 'vintage' tube in it...absolutely not.

I wouldn't, but I like equipment that is flexible as I gou through the adventure of finding my best sound. 

Soon there might be neither Chinese nor Russian new tubes available if the trade is stopped, so you better get a supply of them. Not my problem, I stay with vintage. You see, there is an unexpected advantage, in addition to expected advantage.

Back in the late ’90s I was running a Cary SLP-90  with 12au7s in front of a pair of ARC VTM-120s that were configured with four 6550s a piece with some 6922s in front of them.  I talked to Andy in Michigan and he sold me some NOS Mullard 12au7s for the pre and some NOS Amperex 6922s for the amps. After those tubes broke in a bit, that combination sounded fantastic.  At the time I was running the amps with Svetlanta 6550s (either the 6550b or 6550C, I cannot remember) and I was so happy with the results of the other tubes Andy sold me that I called Andy back again and this time he sold me two quads of either NOS or vintage used Tung-Sol 6550s.  Those cost me what I thought was an arm and a leg back then and I honestly couldn’t hear improvement.

I am not using the Cary right now and the ARCs are long gone; the stereo amp I am using right now takes a dozen EL34s and there is no way I am going to lay out what it would cost to go vintage used or NOS in that. 

Vintage used could be $100 each, but if you wanted to match dozen EL34 tubes..that would be a problem. And, yes, you couldn't be sure in advance of significant improvement. Well, vintage tubes were not created equal.