Please, who do you think the truly great composers/recordings are now in the 21st century?
The search for music that you will treasure three decades from now seems to be the problem from the start. No other music genre demands that of its listener, and often it is difficult to know at the time what you will treasure three decades from now. As far as recordings, I think there have been a lot of amazing recordings done in the 21st century, and there are dozens of great conductors, orchestras, ensembles, and thousands of individual musicians who are outstanding. At least as good as in previous eras. The biggest difference is the audience.
Classical enthusiasts tend to be very dependent on what people at the time thought or said about a particular recording or performance. Take Bach's cello suites, for instance. I'm listening to a remastered version of Janos Starker's 1950s and 1960s recordings in high resolution (176/24). It sounds great, and it is truly amazing playing. But to say that it surpasses, without a doubt, all of the recordings done in the past 15-20 years would be very naive. If I buy a new recording, I'm not necessarily looking for the one I will listen to in 30 years, but rather the one I want to hear now.
I don't actually know that many living composers I enjoy or would compare to Bach, Beethoven, or even Sibelius. Still, I'm a fan of many 20th century guys like Bax, Britten, Cace, Takemitsu, Walton and others.
Again, no one goes out to by a rock or hip-hop album with the intent of finding the one they will cherish until they die. It's completely over-the-top. Why do that with classical? Many of the small and mid-sized record labels, like Bis, Alpha, CPO, Linn and Hyperion, among others are putting out great new music, and new recordings. I stay away from Decca, DG, and other big labels, but that's not to say they're bad, I just prefer to have a fresh look on things. It's the conservatism of the genre that generally means the big-label stuff frankly sucks in comparison to the smaller ones.