Somebody had asked this before, and I couldn't find the thread it was in, so I thought I'd just start a new one.
In going over the material more closely for the chapter summaries (I'm getting more succinct with those -- huzzah!), I noticed that when Telemachus called that general assembly, one of the people who spoke up was Mentor:
"Odysseus' friend-in-arms to whom the king, sailing off to Troy, committed his household, ordering one and all to obey the old man and he would keep things steadfast and secure."
We can understand why, with all the good intentions in the world, this man wasn't able to keep the suitors from taking over as they have -- Mentor was old even when Odysseus sailed to Troy, and that was twenty years ago.
I don't know if Homer made up Mentor's name; but the Homeric verb "meno" means "to remain, to wait, to withstand." Which seems appropriate.
My Homeric dictionary points out that Athena disguised herself as Mentor when she urged Telemachus to sail off that night to Pylos and Sparta, and therefore became a mentor to Telemachus. Surely Mentor himself often stood in such a fatherly stead. Odysseus the crafty wouldn't have left his household in the hands of a fool.