I am increasingly convinced that 95% of the good Pundit's posts are actually for troll value and the other 5% makes sense. As per the law of averages, this was one of those posts that doesn't make sense. IMO there are more opportunities in Middle-Earth for "epic adventure" than there is in the Star Wars universe even under the criteria stated.  

As many have pointed out the unwritten Fourth Age is a place of many epic opportunities. Ran a few AD&D games and then Rolemaster set in the Fourth Age of Middle Earth myself as a youngster. ICE were well aware of these opportunities and always spoke of FA middle-earth in their campaign packs.

Fans of The Silmarillion will not let the Second Age go past of course. Personally, I think the Fall of Fingolflin is one of the finest pieces of English literature.

There is also those two Maiar who went a-wandering (Alatar and Pallando) out of the NE corner. They sure weren't doing nothing during the Third Age.

One other approach I also think is obvious is basing settings by exploiting turning points in Middle-Earth's history. What if Frodo failed in his quest? What if, by some strange instance of luck, Fingolflin did slay Morgoth? Or Gondolin withstood the assault? Melkor finds a way in from the Doors of the Night? How about recovering that silmaril that was cast into the sea (I used this as a plot for a Fourth Age game)? Is the Dark Land (no, not Mordor the other Dark Land) truly empty of opportunity and adventure?

I find this sort of approach works well in historical roleplaying as well. Pick a turning point in time, and let the character's run loose and see what happens. Heck, there was even a time traveller game (TimeMaster) which had modules for such events and explanations on what happened to history depending on the deviation from the historical expectation.

I've never seen that much potential in Middle Earth as a setting, I have to admit.

Which, to be blunt, is a failure of imagination on my part.  Because I have seen tons of great sounding campaigns described online.  Clearly it works, because a load of people run Middle Earth games with great success.  It just doesn't personally inspire me.

And that's the thing, just because one can't see how a licenced setting would work doesn't mean it won't for anyone else.

That said, Middle Earth is not that small and you could easily do other events in the third age, second age stuff or stuff during the reduced magic period of the early fourth age.  That last option could work very well for a lower key game, with a variety of threats remaining and with magic even rarer and more mysterious than in the third age.