I suspect this affects many developers who cut their teeth on PHP but haven't kept up. The language has become a different beast, which is a strength for the community but a barrier to re-entry.
If you pull out examples of the earliest C, sure, it looks weird. But that C was already obsolete in 1989. Since then, it’s had a minor iteration (e.g. five-eight additions/modifications) every decade-ish (99, 11, 17, 23). Has it changed? Sure. Can it be compared to the iteration and speed of things like C#, Java, C++, etc? No way.
“Actually, one of the most notoriously conservative and simple (in feature set) languages is really super complex and has evolved a ton because it has _Generic and varargs now, and __packed__ exists as a compiler feature.”
And to further double down, that minor evolution is over 36 years (arguably a decade longer, but I’m being generous with your argument). Not the 12-16 years (depending which 5 point release you wanna start with) that PHP has morphed into an entirely different language.
And I would double down on my bet regarding ISO C related questions, as I have met a few folks that contrary to myself as language nerd, hardly know what is written there or have even opened the PDF drafts at least once in their life.