System administration is a very reactive role, with sysadmins constantly monitoring networks for issues. Systems engineers, on the other hand, can build a system that anticipates users’ needs (and potential problems). In certain cases, they must integrate existing technology stacks (e.g., following the merger of two companies), and prototype different aspects of the network before it goes “live.”
In other words, it’s a complex job, with a salary to match. …If you want a truly impressive salary, though, consider specializing in Linux systems—that will translate into a $20,000 pay bump.