One way of looking at this, is, Is it the Data/Original Bits/ "Music" you are interested in, or the replay chain associated with a given format.
If you view shiny plastic discs as a delivery mechanism, with the content being the important stuff, we can say:
Redbook CD: content can be liberated from delivery mechanism DVD-A: content can be liberated from delivery mechanism SACD: content can be liberated from delivery mechanism - indirectly
However, with advances, such as mores law, and the rise of commodity distributed computing. e.g. Amazon's EC2 brings new might to password cracking ? The Register
You could say that Sony needs to be lucky always, we just need to be lucky once
SACD is still vulnerable to the Analog hole - Wikipedia, the free encyclopedia. Given a player, and ADC of your choice you could make Needle Drops (SACD Drops?) of your favorite disks, and never have to remove them from their cases again.
This raises the question , are you listening to the original bits, or artifacts of the replay process(x2) - but that's another discussion.
With the advent of unencumbered formats that support hi-rez (to the bit width/depth of your choice) and low marginal cost digital distribution (thats downloads to you) it raises the interesting question of cost vs value.
If the studios mastered in the digital domain, should it cost more or less to just release the original bits, vs the (not very onerous, admittedly) "extra" expense of downsampling/converting to a more limited resolution
(e.g. 24/96 masters vs 16/44.1 redbook)
And how hard/expensive would it be to replay the analog masters, on a decent, newly cleaned replay heads, setup, in front of a decent ADC, (or several, each running at the target sample rate/bit depth), and then selling the results?
We live in interesting times.