The SAN is usually less of a single point of failure because they usually have a lot of redundancy built-in, redundant storage processors, multiple backplanes, etc. You're right that off-site replication is still important, but usually more for whole site loss than storage loss.
People assume the biggest source of SAN failures is a hardware failure, and believe hardware redundancy makes SANs less likely to fail. In my experience, that's false. The biggest source of SAN failures are (usually human-) induced problems from the outside. Plug the wrong FC card with the wrong firmware, knock out the switching layer. Upgrade controller incorrectly, bring down SAN. Perform maintenance incorrectly, wipe the array. SANs go down all the time, and often for very difficult to predict reasons. I saw a SAN that no one had made any hardware or software changes to in months just suddenly crap out when the network that connected it to its replication partner began to experience flapping which noticeably affected no one except the SAN, which decided a world without reliable replication was not worth living in and committed suicide by blowing away half its LUNs.
Keep in mind the last time I saw a hard drive die and take out a RAID array was so long ago I can't remember. However, the last time I saw a RAID *controller* take out a RAID array - and blow the data away on the array - was only a couple of years ago. Its important to understand where the failure points in a system are, particularly when it comes to storage. These days, they often are not where most people are trained to look. Unless you are experienced with larger scale storage, you're not trained to look where the problems tend to be.
Storage fails. Any vendor that tells you they sell one of something that doesn't fail is lying through his teeth. Anything you have one of you will one day have to deal with having zero of. It doesn't matter how "reliable" the parts in the one thing are. You should plan accordingly.