Don't be silly. Optical disks are close to end of life, superceded by flash memory as they are.

Consumers are getting used to the idea of moving data around on memory cards and USB sticks, and we're mere moments away from small form flash that holds as much as a blu-ray disk (if it hasn't happened already).

Its hopeless as a random access medium so its really only suitable for long term storage of data where if you need the tape in an emergency you usually need most of whats on it. Even in a long term storage situation however its not all that trustworthy as tapes are easily damaged or chewed up and deteriorate anyway as the magnetic signal slowly leaks away or is effected by nearby magnetic sources. A combination of solid state storage and optical media is probably the way forward though perhaps something new will come along soon that will trump even those.

When should we expect the next cart-based console? Flash drives have one advantage that's often overlooked: durability. If you step on a disc, it's game over, whereas the rigid plastic around the chips will survive(and they don't get scratched).