I will put forth an opinon--I hope it is not too controversial, but here goes:
Myth: Your proprietary raw files may be orphaned one day by the manufacturer, leaving you unable to open your images.
I don't think I've ever properly understood this argument that Adobe has been advancing for years. Ironically, Adobe is the producer of one of several of the 'swiss army knife' demosaicers which let one develop hundreds of different raw formats, even discontinued ones.
Can anyone point me to a proprietary camera raw file format that has existed that cannot be opened today? I've never heard of one...
I've been shooting digital since 2000, and involved in computer graphics and imaging since 1987--even now I can't think of an image format that I once used that I can't open today--that's 22 years...
To me, Adobe is spreading
FUD, designed to frighten people into adopting this format.
Please don't mistake this for an anti-Adobe position. If any manufacturer came to me today and asked what mosaiced file format they should have their camera/digital back write, I would push for DNG. Not because a proprietary format is dangerous or will be orphaned, but because fewer formats are better for me as a user. I'd say the same thing if a manufacturer asked me about a lens mount. Manufacturers invest in proprietary file formats and proprietary lens mounts for valid business reasons. I am just saying that in the end, the 'orphaned proprietary file format' argument for DNG just doesn't seem to hold water.
Fact: Using a proprietary raw file complicates an already complicated digital workflow.
I certainly can't deny this. But the question I pose is, is it the
PROPRIETARY raw file that makes this more complicated, or the fact that
ANY raw file (DNG included) makes it more complicated? IMHO, it is the latter that is the issue.
I cannot move any mosaic'ed file to any OS and fully utilize the file. Apple, Windows, Linux all require additional software (iPhoto, WIC codecs, DCRaw, or 3rd party applications) to manipulate a raw file. Apple is doing the best job with CoreImage--many raw files are at least readable by the base OS (eg. Finder), although transcoding or editing requires additional software. To their credit, they often ship iPhoto pre-installed.
So I'll argue that the problem here isn't whether the raw format is proprietary, it is the fact that it is a raw format.
(Note: I had a small supporting role in helping to bring about the new JPEG-XR standard, so I must disclose this in order to allow others to decide if I am biased or have a conflict of interest.)
Going forward, I believe this issue will go away for 99% of us. Once JPEG-XR begins to appear in cameras, the need to deal with raw files will be nearly completely eliminated. Why? Because 100% of the information contained within a raw file can be encoded into a JPEG-XR file (no loss),
and the manufacturer can decode the file in-camera, giving us the photographer the default colors and look intended by the manufacturer. If you have used raw developing software in the past decade you have already seen that the best looking files consistently come from the camera/back manufacturer's software, but that software is frequently buggier, slower and more cumbersome than 3rd party (ie. Adobe or Apple) software.
In this way you get the look the manufacturer intended without having to do any extra work. The camera delivers a fully useable (demosaic'ed) JPEG-XR file which may be 100% lossless for quality or lossy to save space (your choice). The JPEG-XR file, which is a "normal" image file will be transportable and useable just about anywhere a JPEG file is today.
There is one drawback to this approach, that only the pickiest of the picky will get held up on, and that's the fact that because your image gets demosaic'ed at the time it is captured, you will not be able to benefit from advancements in demosaicing technology as time moves forward. Today, if you open your raw file from 2000 in Lightroom 2.4, theoretically, it could look better than it would have had it been developed 9 years ago, because demosaicers are better today. In practice, though, this is not a significant concern.
Conclusion
So I hope I have helped you breathe a little easier. My suggestion is to hang on for another year or two (just keep doing whatever works best for you) until the JPEG committee can get the standard finalized and into the hands of the camera manufacturers and into shipping products. Then I predict most of us will be shooting JPEG-XR and won't need proprietary software to manange the files. Until then, feel free to use either DNG or your manufacturer's proprietary raw files without fear. You will be able to convert everything you wish (should you wish to) to JPEG-XR at that time, en masse. Even if you do not convert your work to JPEG-XR, I would be shocked (yes, shocked!

) if any proprietary raw files were 'unreadable' even 25 years from now.
I'll save a discussion around archiving (>25 year access) for another time.
Best regards,
-Brad