I've heard the same finite longevity theories, but have yet to hear of a confirmed failure. That does not mean it's not true. I'm a commercial photographer and I do store much of my work on CD and DVD media, so the issue does concern me.
On a related note there is some interesting data about DVD media quality. Most of the big manufacturers that you buy at OfficeMax/Depot/Staples, etc. are rebranding, or rather buying cheap media out of Taiwan. It is particularly annoying with some DVD-R/RW media that consistently fail to burn. There is some good information about locating quality media here, which will refer you to a link to download freeware that will help identify the media you are using. I won't go further as the site can explain it far better than I.
Marco
On a related note there is some interesting data about DVD media quality. Most of the big manufacturers that you buy at OfficeMax/Depot/Staples, etc. are rebranding, or rather buying cheap media out of Taiwan. It is particularly annoying with some DVD-R/RW media that consistently fail to burn. There is some good information about locating quality media here, which will refer you to a link to download freeware that will help identify the media you are using. I won't go further as the site can explain it far better than I.
Marco