I'm not a philosopher by any means but I do believe that philosophy is actually the history of philosophy (or a very close approximation of that), and for that reason Hegel or Thomas Aquinas or Epicurus are as contemporary now when it comes to philosophy as they were when they were alive.
Yes, there are ups and downs in their reception (for example the philosophy of Thomas Aquinas has had a long hiatus from public perception in the 1700s and the 1800s) but that only happened because of our different way to read/interpret the history of philosophy hence philosophy itself (the materialists in France and the empiricists in Britain weren't that fond of Aquinas).
There are a lot of useless detours, as well as survivorship bias and namedropping. Added to that is the deliberate obtuseness of certain so-called philosophers. I wish philosophy were as noble as what you seem to believe.
Yes, there are ups and downs in their reception (for example the philosophy of Thomas Aquinas has had a long hiatus from public perception in the 1700s and the 1800s) but that only happened because of our different way to read/interpret the history of philosophy hence philosophy itself (the materialists in France and the empiricists in Britain weren't that fond of Aquinas).