My copies of The Lion King (Platinum), Aladdin (Platinum), Alice in Wonderland (Special Edition) and Sleeping Beauty (Special Edition) all have a mention of DVD release year somewhere on the bottom of the back (the 2004 ones are found in a box on the lower right, the 2003 ones listed alongside the other main data points). The Gold Collection ones I have do not seem to have any mention of their respective years, but those were all originally released in the summer of 2000. I think this is just Disney's standard practice now, and not a sign that there's any unusual plan to discontinue them or release a new version any time soon.
I don't have any live-action Disney films yet to crosscheck with, but I really don't think this should be of any concern.
I wasn't too worried, I just thought it was a tad odd. The last 3 Ghibli releases didn't have anything of the sort...and I never really stopped to inspect the Aladdin/Lion King cases.
