I honestly think BLACKBIRD's play-or-revival status is a legitimate question mark, more so than some other recent examples (CRIPPLE OF INISHMAAN, THIS IS OUR YOUTH, etc). It's not a new play, but I would imagine many will argue that it isn't well-known or produced enough to be considered an "established classic".
"You travel alone because other people are only there to remind you how much that hook hurts that we all bit down on. Wait for that one day we can bite free and get back out there in space where we belong, sail back over water, over skies, into space, the hook finally out of our mouths and we wander back out there in space spawning to other planets never to return hurrah to earth and we'll look back and can't even see these lives here anymore. Only the taste of blood to remind us we ever existed. The earth is small. We're gone. We're dead. We're safe."
-John Guare, Landscape of the Body