I think it might actually be somewhat accurate. There are 6.25*6*24*365 new bitcoins created every year and given to miners. That's over $6B at current prices. So it sort of makes sense miners would spend $6B/year to acquire those $6B of new bitcoins. And that isn't factoring in transaction fees that miners also get, nor that this article was written in June when prices were a lot higher, meaning it would have been much more than $6B/year if I did those calculations then.