RAID as a concept will die. When is the question, but as drive sizes are getting larger, it will be up to the storage vendors to come up with technologies that potentially replace this...
... or is it really up to storage vendors?
One of my favorite examples is BackBlaze. These guys are a provider of unlimited cloud backup for your desktop. They're talking about server backup later, but here's what's interesting. They talk about their hardware platform quite a bit, basically it's a Linux server running tons of common hard disks in a custom chassis.
Take a look at their solution here.
What makes their pod so unique? It has NO RAID. Zero. Instead, they have developed an application framework for their business that builds data redundancy and replication into the mix at a higher than hardware level. Their hardware is uninitelligent, and provides no failure-protection. If a pod dies, they don't care. Reason? They replicate the data to other pods. Their software detects a hardware failure, it can start creating a new copy of the data on that pod elswhere.
Google does something very similar. They distribute their storage over thousands of COTS hardware nodes, and build fault-tolerance at the software layer.
Lets look at the a futuristic file-system, ZFS. ZFS has RAID capability built into it. In fact, if you want to use ZFS instead of a NTFS filesystem, you don't use a RAID controller for smaller disk-sets, and for larger sets you may stripe a few RAID arrays across into a RAID-Z. You want to present the disks as JBOD or RAID0. ZFS handles the failure, handles the data integrity, and does a better job of it.
Unfortunately, there's still a rebuild process that takes a large amount of time... 20 hours for 50TB or so, hardware-dependant. Current solutions now don't address the time it takes to rebuild from failure.
So the future will be about pushing fault-tolerance away from the hardware. Abstract the hardware in a virtual solution, and manage the data from that level. Then you can replicate, apply parity, calculate checksums- do what ever it takes to keep the data available. Corey mentioned the IBM SAN Virtual Volume Controller, and that's a step in the right direction. Abstraction.
But how about now? How do we achieve resiliency without worrying about hardware vendor technology and without resorting to relying completely on RAID?
As an IT solutions provider, I've had my share of disaster recovery situations. Those that end up the best are those where there was a replicant of the data that was lost.
That's why I don't prefer RAID5/RAID6 alone.