Neither parallel programming nor quantum computing is going to save the day without massive unprecedented breakthroughs. It's a hard ware problem, and we won't know how hard until we solve it.

We don't use parallel systems efficiently today because we don't have software systems that provide typical programmers with a human-comprehensible interface to program them. Writing efficient, correct parallel code in traditional programming languages is very difficult; and some of the research languages which promise automatic parallelization are on the high end of difficulty for humans to learn.