Sure, you absolutely can use a limited set of C++, and find value, and there are many big projects that have gone that route.

See Embedded C++ - https://en.wikipedia.org/wiki/Embedded_C%2B%2B

Apple's IO Kit (all kernel drivers on macOS/iphoneOS/ipadOS/watchOS) is a great example of what you're talking about. Billions of devices deployed with code built on this pattern.

That said, in the embedded world, when you get down to little 32-bit or 16-bit microcontrollers, not amd64 or aarm64 systems with lots of RAM, pure C is very prevelant. Many people don't find much value from classes when they are writing bare-metal code that primarily is twiddling bits in registers, and they also can't or don't want to pay the overhead for things like vtables when they are very RAM constrained (e.x. 64kbyte of RAM is not that uncommon in embedded).

So, I disagree with the idea that "actual uses of C are esoteric" from the post - it's very prevelant in the embedded space still. Just want people to think about it from another use case :).

The classic example of a big pure-C project at scale is the Linux kernel.

Ask Linus what he thinks of C++. His opinions are his own (EDIT: I actually like C++ a lot, please don't come at me with pitchforks! :)), I merely repost for entertainment value (from a while back):

https://lwn.net/Articles/249460/

Maybe a simpler example: go find a BSP (board support package) for the mirco of your choice. It's almost certain that all of the example code will be in C, not C++. They may or may not support building with g++, but C is the lingua franca of embedded devs.