I had the same thought, "oh damn, I haven't heard about 'the c10k problem' in ages" :D (it was "solved", right?)

Given the author, his history in the field, and the project, though, I'm confident the repetition is intentional.

Like a contemporary rapper dropping Doom bars on a track, I read it as an homage / callback / shout-out, even if the meaning is changed.

Yep, and that problem is history now. Just like c10k from curl will be history.