... Resorting to conspiracy theories about secret hidden data troves doesn't help make us Canon users look any better.
You know what is really silly?
Not believing your own eyes.
So you really believe that the full frame 5D Mk III has the same dynamic range as the original 2003 APS-C Digital Rebel (300D)?
Now that's silly, but, according to DxOMark they do:
5D Mk III - DxOMark Maximum Dynamic Range (screen) - 10.97
2003 Digital Rebel (300D) - DxOMark Maximum Dynamic Range (screen) - 10.93
What is silly is comparing them at screen level when one camera has 22.3MP and the other has 6MP. Look at the print comparison and it puts it 1 stop better than the 300D. (It also puts it only 1/2 stop better than 40D, which also has a lot less banding, so they are perhaps about the same usably, which seems to match what I see)
(granted it's IS also silly and a bit shokcing that Canon made the 5D3 barely better per photosite for maximum DR than even some of their older DSLRs and a tiny worse than any recent one, but it's true)
Canon had world beating SNR and low ISO and high ISO DR once upon a time and then they sat doing nothing, bragging about how they were infinitely far ahead and could just sit around. Now they are still up there for SNR and high ISO DR but have fallen miles behind for maximum DR and yeah they are basically where they were over half a decade ago (and even more if you go by per photosite).
5D3 is pretty awesome in most ways, no doubt, generally a great cam but the DR has disappointed me and I have to say I was quite shocked it wasn't a big step up from the 5D2 in that regard and even more shocked that it was actually worse, even if to a meaningless degree (and it would've be super awesome it if it had 28-30MP and still had 6fps and if it had video focus peaking (Canon simply NEEDS to add the latter in firmware)). If it had that I bet the price would be easily maintaining $3500 (at worst). I just hope they are able and care to fix up DR for the 5D4.