I'd be very surprised if the C/C++ code being written today was comparable in volume to the collective pile of JavaScript, Java, C#, Go, Python, and PHP.
Contrast to the heyday of C and C++ when not much else got a look in (Pascal perhaps? Perl probably...)
I think it's fair.
hmm how can I reuse this useful Go library in python... Oh I can't.. hmm and how can I reuse this useful java library in php ? Oh I can't. Oh and which of the programming languages you mentioned can and do use C libraries? All of them.
Reminds me of that coworker who thought that OpenCV was basically written in python.
Yes, surely much more code is being written in other languages than in C, but probably more C is being written now than ever before, too.