[EvilTrout]

This is a good question and the answer is it's both.

It requires a completely different approach to programming so many programmers haven't made the leap. Additionally, some kinds of software problems seem to be unparallelizable by default.

Having said that, there is an advantage to a many-core machine right now: you can run many tasks (programs) simultaneously. Even if a program can only use one core, your OS should be smart enough to run it on its own core.

Of course then they might contend for other resources, like disk or video throughput.