As I’ve said before… losing that much data will be a big issue for consumers. Blu ray discs have not proven their long-term viability yet either and much of the OD industry’s reputation & future will rest on that: the current standard; along with competition from flash media & HDD.
Part of the reason why HDD’s take so long to develop these days are because they KNOW that consumers demand a 3-5 year window on data integrity along with intelligent sector re-mapping. If optical discs hope to accomplish greater viability in higher densities, they will have to be of the re-writable cartridge type (of course, backwards compatible with ordinary discs as well) with technology similar to HDD or mount rainier format.
Pricing will also be a big win or fail determining factor.