The thing is, the Glory Days when kernel development was a scary, exciting wild west are lone gone.
By necessity, the Linux kernel is now a part of the tech firmament and development is necessarily not as sexy as it used to be. So it's gonna be tough to get people to pay to read about it.
It just mirrors internet culture as a whole. Easy to consume information, show off and fashion.
Lest aspiring systems programmers get the wrong idea: systems knowledge is still black magic and it's still plenty valuable. Knowing how systems actually work under the hood is a rare skill and can help you code circles around the node-is-close-to-the-metal [1] competition even when writing application code.
[1] https://twitter.com/shit_hn_says/status/234856345579446272
For example, as of right now, most of the articles on the front page aren't about kernel development: distro security updates, LibreOffice, Firefox, GnuPG, ...
I think this is perhaps an overlooked aspect of Linux's success; at a critical time, they had LWN and good documentation that made it easy for new developers to understand what's going on and start contributing. I don't know any other open source project that is as accessible to new developers as the kernel was in the early 2000's.
I think in the last few years many open source communities have become a lot better than the kernel in terms of having good starting points for beginners. In the last 5 years I think many projects have started to focus on developing and improving community process, which is good.