Neither clumsy nor funny (Well, maybe funny to some).
I confess, the notion that one can "write down what cannot be written down" did indeed strike me as ridiculous. But as a joke, it's a bit of a cliché. I've heard it intentionally stated as a joke dozens of times.
At any rate, let's dissect this frog a bit, so to speak. In the first place, there is more than one kind of knowledge, isn't there? Ask any psychologist and he or she will tell you that only some -- but not all -- knowledge is "symbolic" or "conceptual". Some psychologists will even tell you that
most of what you know -- most of what you have learned in life -- is non-symbolic, non-conceptual knowledge.
Now, this non-symbolic, non-conceptual knowledge cannot be transmitted, taught, communicated, shared, etc symbolically, conceptually. All you can do is "point someone to it".
By "point someone to it", I mean you can tell
sometimes tell them where or how to find it. For instance, what it feels like to have really great sex is for the most part (but not entirely) non-symbolic, non-conceptual knowledge. You can tell me all day what it's like, and if I have never experienced really great sex, then there are things about it I just won't "get" no matter what you say. Maybe I think I understand you, but once I actually do have some really great sex, then I will realize I didn't understand you much at all. So you can't for the most part tell me what really great sex is like, but you can tell me where to go for it, how to have it, and so forth.
By almost all accounts, enlightenment comes about via an experience or series of experiences that -- among other things -- appear to impart some non-conceptual knowledge. HOWEVER, it is highly debatable just how important that non-conceptual knowledge is to someone's being enlightened. Who knows whether it's key or not? Maybe enlightenment isn't brought about by any kind of knowledge at all, but is instead brought about by some re-wiring of neurons in the brain such that information is processed differently now, processed in an "enlightened" way.
It would seem that eventually everyone should be enlightened (by what ever definition one uses) because the supposed knowledge would be shared.
That strikes me as like saying, "Someday everyone will know what it is like to have a really great orgasm because the knowledge can be shared." Sounds pretty assumptive, if you ask me (not to mention ridiculous). For all we know, only a relatively few people have any chance at all of enlightenment. There does not seem to be any natural law that says you must be able to orgasm, nor does there seem to be a natural law that says you must be able to attain to enlightenment.