Lisp has had some extremely vocal advocates. Paul Graham, certainly. "Beating the Averages" has attracted a lot of attention, outside its typical niches.
Also, Lisp has been around for a while - it's been a couple decades ahead of its time for fifty years! Much great research literature has come out of its culture.
Besides, Haskell certainly gets plenty of "blog posts by people who almost certainly don't use it on a day to day basis". Erlang's culture seems to favor ugly pragmatism over "avoiding success at all costs", though.
Also, Lisp has been around for a while - it's been a couple decades ahead of its time for fifty years! Much great research literature has come out of its culture.
Besides, Haskell certainly gets plenty of "blog posts by people who almost certainly don't use it on a day to day basis". Erlang's culture seems to favor ugly pragmatism over "avoiding success at all costs", though.