But nobody stores stuff on 1,000 DVDs; they use tape storage, which maxes out at 1TB per tape.
Who wouldn't trade 2 random access 500GB discs that can be switched out in seconds for a 1TB tape that takes 62 seconds to mount? Everybody would and will.
I do agree with your point, except the everybody bit. It depends on the market and what type of data you're talking about. On the corporate backup system I look after, we fit over 2 TB on a tape, which costs about $100. It takes about 15 seconds to load and another 10-15 to locate to any position on the tape. When you're talking about backing up multi-terabyte databases, 30 second access time is not a big issue. I see up to 160 MB/sec throughput, with hardware compression. That's 160 MegaBYTES per second. The drives are rated to about 250 MB/sec, so I think the bottleneck is our crummy old 2Gb/sec FC switch. And tape is rewritable. There are several thousand tapes in our libraries.
Admittedly, the drives cost in the tens of $thousands, and the robotic library in the hundreds of $thousands. But my point is, I can't see everybody abandoning tape for holographic storage in the near future.