Science is in the business of answering what is. It can't answer normative questions, i.e. those about what ought to be. That, at the very least, is one of the domains that philosophy is still both sensible and productive.[1]
As others have pointed out below, this article was written from the analytical perspective -- the tradition that stands in contrast to continental thought and critical theory.
[1]: Which is only to say that only a single counterexample is needed to invalidate a claim about "all the big questions." There are plenty of fields besides ethics where philosophy inquiry continues to be relevant and productive.