Like I said, if you want to write for orchestra you might as well get used to Midi or whatever, since chances you'll never get played. It's just how it is. You can write a piece for space shuttle and the sound of braking 2000 year old Chinese relics, too! But it doesn't mean that'll happen.
You can say it's pessimistic, but it's just simple 1+1. There's no way you can compete with the standard repertoire, you'll lose every time and unless orchestras start dedicating much more time to new music, they lag behind everything else. It's -extremely- rare for any orchestra to play new music from anyone who isn't already rather famous.
The only chances are when where you study has an orchestra, but you can't count on this either since not all programs work that way.
So no, I'm not saying people shouldn't write for it, but I'm saying they have to be realistic. I don't write for orchestra because I think it's a waste of time, even if I can imagine things to do with it, it's all extremely far fetched and it's ultimately too frustrating to bother giving it more thought.
Oh and I'll address this bit of crap real quick:
"Classical" music, eh? People still play Bach and Beethoven nonstop, I dunno if you noticed.
People who actually play and listen to 20th century non-pop music are a minority, if only out of ignorance, fear, and laziness. Who knows if it communicates anything to anyone, if nobody knows it since nobody plays it? It's a self-fulfilling prophecy overall.
I don't care about music "communicating" anything, but the disconnect is obvious even within "classical" music, as again, almost nobody performs music that isn't from the 19th century and back.