[WkndTriathlete]

Not an apples-to-apples comparison.

Take the K&R C book. It describes the language itself only - not the standard library. The Kotlin docs describe the language _plus_ parts of the Kotlin standard library which is why it appears to have lots of features. You'd have to read through half the standard C library documentation & pthreads docs in addition to K&R C to get the equivalent experience.