A lot depends on how "systems software" is defined. Very few people have much use for a whole new kernel. Even little pieces of new kernel code are less useful than before, as various functions (e.g. storage) can be handled just as well in user space. So if "systems" == "kernel" then relevance really has been declining. On the other hand, if one considers "system" to include user-space storage and networking, distributed consensus and service discovery, package and system management, JIT and GC in language runtimes, etc. etc. etc. then we're actually in a bit of a renaissance.
The fact is that kernel/user hasn't been a very interesting boundary for a long time. There are hundreds of systems-programming problems that can be solved on either side of that boundary, except that if you try to solve them in the kernel debugging will be harder and you'll get embroiled in the constant turf wars that are the hallmark of a declining specialty. The idea that only kernel hackers do systems programming needs to die.