For people new to pipes, I can both understand the frustration and suggest it's really not a big deal. Sure, it's lamentable to see fine blends (and blenders) disappear. Certainly, I miss greatly Troost Slices (Van Rossem's) and Frog Morton (original). I haven't found something to replace either one, exactly, but I keep looking for blends I like as much with similar profiles, which is part of the fun of exploring.
As has probably been pointed out many times before, though, there are still available some of the finest blends ever made (in my opinion)...and they are largely always in stock, can be easily ordered off the internet. While I'm no expert, I've been sampling widely for almost 30 years and early on tried many great tins from the 50s-70s, as they were more curiosities then than collectibles and priced accordingly.
Just a few examples of some blends still available that may rank among the legends of old (to my own taste):
Peretti blends -there are quite a few (and I think the company offers samplers). Tashkent maybe my favorite oriental ever
RO Perique Sereis - GP-11 is particularly nice but they are all worth trying to find one you like
Robert Lewis - for the English blends. Production on these must be pretty low, as they go out of stock relatively quickly, but nothing like Esoterica or others. Orcilla Mixture is a good one to try.
Watch City Cigar - Ernie has a some great blends, there was a cavendished oriental that is no longer around, but he makes some amazing slices
HU Tobacco - I've tried most and like all of them, at least half a dozen are among the finest tobaccos I've had (has to be ordered from Europe, so shipping can be a pain)
Even more widely available, I like:
SPC Plum Pudding
Ashton Artisan's Blend
Savinelli Doblone d'Oro
HH Aniversary Kake
Magnum Opus
Pease Samarra, Quiet Nights, Union Square, Westminster (really quite a few)
SG Skiff blend is a little harder to find but not unobtainable. Definitely worth it, in my opinion.
There are so many really. There was a thread recently about Cabbie's Mixture, which I hadn't tried in a while but cellared a few years back. I forgot how good that one is. It's probably available now, too.
Cheers and Good Luck!