The diversity of media including hard drives are VIABLE options. I recently seen a 3TB hard drive on sale for $129.99 with free shipping!! Even DVD's would have a hard time competing on price considering the acutal task of recording 100's of single layer dvd's vs just slapping data on a hard drive (or two, one as backup). While dvd's have a slight edge in cost on the single layer, the time & convenience factor weighs heavily. Dual layer and blue ray costs aren't really worth converting data just yet.. even though I do record data to blu ray. It's an expensive media $1+ per 25gb disc!
Tablet computers make online storage a better option for consumers as well. Once you have about 16 - 32gb in onboard/fash media storage, you can put the rest in the cloud and swap in/out wirelesly. In this sense if you have an HD move you want to watch on a tablet, BLU-RAY becomes outmoded.
This is why as demand drops, so will the prices.. never before has so many kinds of storage options been available. It's also pretty safe to assume most online / cloud storage is taken care of by hard drive arrays, not tape and/or optical disc (unless it's mission critical data, for extra security).