The road to DNG is two-way. Or, to put it differently, most of you guys (including the OP) are
barking at the wrong tree.
First off: I am all for standards, and yes, I would
love to see DNG universally excepted. But let me explain what needs to happen
before you can even start asking Sony et. al. to adopt it.
The responsibility for maintaining the standard has to be fully transferred to an international non-profit standards organization, such as e.g. ECMA (
http://www.ecma-international.org). A good test of how "full" is the transfer should be: if Adobe ever wants to make a change to the standard, they would have to go through
exactly the same procedure as any other ECMA's (or other organization's) DNG committee member. THEN we can call it an open standard.
Those who call DNG non-proprietary today have no idea what they are talking about. Yeah, tell Google, who are currently being sued by Oracle for $1Bn, how open and non-proprietary Java standard is. BTW, I directed development of a JVM variant for a proprietary OS in very early 2000th, so I do have some idea what that all is about.
As was pointed out in this thread, there was a very useful post by an active RAW developer who pointed out several deficiencies in DNG documentation. An esteemed forum member (whom I fully respect for his
photography-related work) answered something like "You can always ask Thomas Knoll". Are we going to also tell that to Sony's CTO? You know what, I can't even make fun of that. For anyone having a slightest idea of what we're talking about here, it already sounds as funny as it gets.
So, if you are really, really interested in wide adoption of DNG:
put pressure on Adobe to let go of DNG before you even start talking to camera manufacturers.
Now, suppose that miracle did happen, and Adobe did pass DNG standard into the little hot hands of ECMA (or similar organization). Will it
then make sense for Canon/Nikon/Sony/etc. to adopt it?
I do not know. What is Sony going to do with its lossy RAW compression (which I believe is simply brilliant; your mileage may vary, please do not derail this thread...)? Also submit it to DNG? What if they invent new compression, how the necessity of jumping through ECMA hoops will affect their time-to-market?
These, and many other questions need to be answered before any groundbreaking DNG-related decisions benefiting us photographers can really be taken... So far, I saw that many forum members just dismiss these questions as unimportant. Well, you shouldn't -- if you are really, really interested in wide acceptance of DNG, and not just in talking about it.