I have always found this poem to be one of the more difficult cummings poems to figure out. With e. e. cummings, it is really important to look at the non-traditional way he uses words because that is the clue to the meaning. Keeping this in mind, this poem may mean just the opposite of what you are thinking, that the meek shall inherit the earth. To me, it is saying that it is a fable to believe the meek shall inherit the earth.
Let's see why I think this. First of all, you can take a stab at rearranging the words of the poem into traditional sentences:
There is a here. Here was a town. The town is so aged the ocean wanders the streets The streets are so ancient the houses enter the people. The people are so feeble.The feeble go to sleep if the people sit down. The light is so dark the mountains grow up from the sky. The sky is so near the earth does not open her eyes. The feeble are people. The feeble are so wise. The people remember being born when. If nothing disappears they will disappear. They will disappear always who are filled with never. They who are filled with never are mostly almost feebler than feeble. It is fable that who are less than these are least. Beyond when, behind where, under un.
Granted, this does not work 100% and we don't know where the punctuation should really go -- and THAT also can totally change the meaning. That said, though, I think the use of the negative words such as "feeble", "dark", "disappear", "never" are significant. Also, examine the use of adverbs, There are a lot of them "here" "there" "when" "where" "never" "behind" "beyond" etc. "Here" was a town. Perhaps he is saying that "Here" is the name of a town -- or here is here, on the earth. It is an old town (see the aged imagery). What does the town represent? Perhaps an old way of looking at things. Perhaps it represents some old wisdom, like the Biblical words, "The meek shall inherit the earth" - or the concept that it is a positive thing to be humble, or "feeble." But then he throws in the word "fable". OK, so is he referring to the fable in a good way, or is he saying this idea of "feeble" being good is a "fable"?
I know I am stirring up the pot here, but try to revisit the poem with these things in mind and see what YOU think.