Flicking through the pages of Rav Sa'adya Gaon's Sefer Emunot veDe'ot the other day, I started to pay attention to the sources he cites in this fascinating philosophical work. I noticed that he drew extensively on Tehillim (Psalms), the Prophets and the Book of Job. However, there were very few references to earlier rabbinical teachings. Some Talmudical tractates were cited, but I spotted no citations from Pirkei Avot. Considering that Rav Sa'adya's work deals with ethical matters and topics such as reward and punishment which are central to Avot, this surprised me greatly.
It then occurred to me that, in all the decades in which I have been pursuing my interest in Avot, I can hardly recall reading anything by or making reference to the scholarship of the Gaonic period (589 to 1038 CE). It would be surprising if no Jewish scholars had anything to say on this most popular and accessible of mishnaic topics for some four and a half centuries.
If any reader can point me to anything I may have missed, I should be grateful. Likewise, if there is an explanation for this apparent dearth of commentaries, please tell me.