A little disappointed that the writer never attempts to address the title of the post, which is either a) why most people can't juggle a single ball, or b) how the author even knows this to be true, aside from some limited anecdata.
My (admittedly limited) juggling experience would indicate something closer to "Anyone can juggle", or that your average person, particularly young people, can learn to juggle one, two, or even three balls with an afternoon of practice, but I suppose that makes for a worse title.
> "Anyone can juggle"
Technically this is not incompatible with the title. Just uses “can” in a different sense. The title would be using “can” in the “has the skill already”, while you use “can” in the “able to acquire the skill” sense.
It is not hard to imagine that most people when asked the question “can you juggle?” would answer in the negative. That’s what the article’s title describes. And then if those people, given sufficient motivation can learn to juggle that leads to your sentence. And they both can be true at the same time.
I agree that it would be nice to provide source for the claim though.