Froma a practical viewpoint, it's hard to see that anything other than downloads will affect recording formats. CDs came in because they were less bulky and less expensive than LPs and much more convenient, durable and smaller than cassettes. A new format would need to present some advantage in order to be accepted.
      DVDs are certainly possible, but increasing the number of tracks on a disc means that royalties and other production costs would drive the price of the DVD way up past what the market will accept. As an example, a company called Juneberry has produced a DVD of old-time country music (MP3s) that contains some forty two hours of music on a single disc. It's almost impossible to sell--for one thaing, there's no room to print a tracklist. And for another, it sells for $35 (US) and folks who are used to spend $15 for a disc won't touch it, even though the per-song and per-hour cost is very low.
    Same thing applies to memory cards and the like. One future development which might have a significant effect on music marketing would be an improved compression system that would permit downloading of music of CD, rather than MP3 qulity.