We don't have that many cores yet. The biggest servers have 64, some phones have 4. That's all within a range where we can parallelize by running different processes on different cores without changing our code.
I guess we will see more urgency in a couple of years when hundereds of cores are going to be the norm. At that point software that makes use of those cores will pull away from software that doesn't.
I'm not saying functional programming will be the answer but it could be. I don't think it's that difficult to grasp.