Do you have the correct source for this quote? I would like see it.
Just Google "
the magic of mining" and an article from The Economist will pop up.
They were talking about mining, and from the previous sentences, i believe they were referring to how hard it is to get the block reward (25BTC in 2015) since it's pretty much a "race" between those with a lot of resources (mining equipment).
Yes @tomahawk9 exactly, in this article they are referring "hard to earn bitcoin" is by mining and their block rewards, we all know that mining requires a lot of equipments which requires a good amount of investment.