If you ask me they mostly need software engineers, not “CS people” especially. Whenever I talk to a scientist about their software, I see great opportunities and interesting problems that are solved in suboptimal ways. To be blunt, scientists can't code (and neither can most “CS people” for that matter). Every scientist (be it physics or CS) could use a professional software people, who have experience with developing and maintaining complex code bases. The problem is, there is no funding. Let's say a researcher gets a budget for some hardware and 10 PhD students, then there is nothing left to pay the engineer with. We're too expensive.