It doesn't sound maintainable at all.
I wrote a proprietary 4GL based on C for multiple platforms for 20 years when there were few standards. It’s doable and maintainable, especially with the standards that exist in the industry today.
The problem, IMHO, is that today’s application programmers - as opposed to systems programmers who write the OS, kernels, device drivers, etc. - are incapable of handling the stack. They code in languages that handle everything for them. It makes for great, object-oriented, reusable code, but it means they’re totally unaware of what’s under the hood. They also have no idea how to open a socket or listen to a port.
The author wrote the article as if the Unix architecture is limited to one kernel/OS per server. It’s not.