Modern philosophers are not necessarily any more knowledgeable or insightful relative to truth than poets or writers in modern times are more insightful about reality than those in past ages.
It could be argued that modern science has improved our technologies such that we can manipulate objects around us more precisely or intentionally, but that mode of advance can hardly be extrapolated to apply without qualification with regard to literature, poetry, the arts, morality, logic, politics, law, psychology, theology, wisdom, justice or philosophy.
Sure, new insights come on the scene from time to time, but whether those insights are significantly more important than insights from the distant past in these disciplines is highly debatable. As is the claim that these disciplines continue to advance in a linear fashion in the same way that technique-based endeavors do.
Sure, areas such as psychology, philosophy and even some of the sciences have opened up whole new ways of looking at the subjects in question, but whether these perspectives are essentially correct or not is still debatable. Is Freud’s view of the human mind essentially correct or even adequate? Does quantum physics capture the essence of physical reality?
Is modern literature substantially better than say the works of Shakespeare, Dumas, Dante or Chaucer? Modern philosophy substantially better than Aristotle, Plato or Aquinas?