Narrow focus

A good many of the mishnayot in Avot -- particularly later in the tractate -- offer propositions that are supported by proof verses from the Tanach.  This is an interesting practice, in that the proposition contained in the mishnah must be taken to say something that the cited proof verse does not say, otherwise the Tanna in Avot would only be teaching as Oral Torah something that was already known from the Written Torah, which would be contrary to standard Tannaitic practice. We can conclude from this that, since a mishnah will not repeat a teaching that is clearly stated in Tanach, the proof verse can never 100% support the proposition contained in the mishnah.

I was looking at some of these supporting verses the other day in my Mikraot Gedolot Tanach, which contains the valuable commentaries of Radak, Ralbag, the Metzudot and Malbim, among others. It occurred to me that, in elucidating the verses I was checking out, none of these scholars made any references to the mishnayot of Avot or to those who had commented on them. This set me wondering: is this merely the hand of coincidence at work -- or is there any principle whereby those who explain the meaning of verses in Tanach do not look to Avot as a means of explaining or discussing them?