A partial answer: the Lord of the Rings (LotR) definitely plays up the "glory of the ordinary" thing: hobbits are ordinary, relatively ignored creatures who end up becoming the Big Heros, saving the world from horrific destruction. Saruman ignores the forest of Fangorn to his great loss. The Battle of the Pelennor Fields would have been one-sided without the arrival of the Rohirrim (themselves a relatively minor neighbor of much older and theoretically more powerful Gondor), but they would never have made it at all without the ignored Drúedain, whose leader Ghân-buri-Ghân shows them a secret path allowing them to reach Minas Tirith in time to save the city.
I find it much harder to understand the David M. Miller's point, quoted above. For me, the thing that keeps Sam Gamgee (and therefore, indirectly, Frodo) going is memories of the Shire, representing homeliness, the simple life they enjoyed before being dragged somewhat unwillingly into the fate of the world. Yes, Frodo has "seen too much" and needs to go into the West with the Noldor, but the others stay behind. So I'm not sure what Miller is trying to say here.