The same applies if you would be using the C subset of a C++ compiler.
I am old enough to remember the days when UNIX and C were funny research projects. Look at them now.
So I leave you with a list of research projects for the boring days, when you don't have anything to read.
I don't doubt that C is not the systems programming language of the future. But it's not going to be done in a system that's based around automatic GC either.
Additionally, I find it interesting to note, that if you had in fact been very familiar with all the work you mention. You should actually have noted that many of these systems go through significant effort to sidestep the GC.
It not just talk about some guys showing up papers at OS geek conferences.
The Oberon Native for example, was for long time the main operating system at the operating system research department at ETHZ. Most researchers used it as their daily OS for all tasks you can think of.
The GC was done at kernel level. Besides Oberon code, there is just a little bit of assembly for the device drivers and boot loader.