Universal also announced that they will begin issuing DVD/BD flipper discs that put both formats onto a single disc. On the surface that seems like a good idea, but I recall that the DVD/HD-DVD flippers were plagued with high defect rates and not especially durable. If that issue is not resolved before these flipper discs go out, that would make for a lot of bad PR for Blu-ray. I'm not so sure that this would reduce the production costs by all that much, but it would eliminate the need for dual inventories (which studios and retailers alike hate) and I think that might be the primary motive here.
Personally I think someone at Universal is smokin crack on this. The HD DVD combo disc cost Universal a fortune to replicate, and then turn around and replace. The bonding that glues the two sides together did not hold, which caused the disc to either rot, or fail after a few months. They had a high failure rate during replication, and often the failed disc made it into the distribution chain and to consumers which they had to replace. The Ant Bully costs Warner a fortune because of the amount of disc that failed and had to be replaced.

Combo disc cost quite a bit of money to replicate, which is why Warner gave up on the HD DVD/Bluray combo disc even before it came to market. The best way to get rid of dual inventory is to do what many studio are currently doing...offering a Bluray disc, and a DVD disc (and digital copy) in the same box. This is cheaper than the flipper disc, and has proven to be quite consumer friendly. We at Disney have gotten a great response from this practice, and plan to continue doing it until DVD goes away.