What sort of jobs are available if I gain expertise in user space level systems programming?

Maintainers. A lot of enterprise customers worldwide run their applications on server clusters on proprietary hardware and Unix. Many of them have been using those legacy systems for decades and have strict downtime limits (for example hospitals) Several companies like RedHat, HP etc with their own platforms earn from support contracts by employing systems engineers for bug-fixing and ensuring the performance meets the SLA. This is more glamorous than it sounds because: It has high profit margins. It takes the same expertise as for developing system software. But one gets to learn and hack around without doing the heavy lifting of the coding. Other than that, there can be library writers and device driver developers, platform and porting work. It's worth noting that systems work is also in danger of being "commoditized". Although it may seem that value-generation is dependent upon the bottom-up view of the computing stack - but it's not really true in the real world. Software without hardware is impossible, but hardware without the software is equally worthless. The closer to the hardware one goes, the lesser room there is for building intelligence. The benefits also dwindle. The philosophy of Google, Facebook and Amazon has been to profit by building intelligence in the application, not in the hardware. They are thriving on commodity x86 servers, while specialist error-free FT-HA platforms have floundered. Once load-balancing in VMs in the cloud works out, it'll be even more banal.