It's wrong, what it says, but it definitely says it.
My (entirely pop-culture based) impression is that "white powder" and similar processed substances of high purity are the dominant form for almost all drugs. Cocaine isn't sold as leaves, nor can you buy dried poppies.
Marijuana is an exception because it easier to smoke in its more natural state and, let's face it, because its users are hippies beholden to the naturalistic fallacy. But THC and that-other-stuff-I-cant-remember are available as concentrates.
Given these preferences, psilocybin is the outlier where, as far as I can tell, only the raw, natural form is available. Since the taste is so awful it's close to legendary, I think we can exclude market preference as a cause. That leaves the extraction being rather difficult as the most plausible explanation, doesn't it?
I miss that, because I have no interest in cocaine powder whatsoever, but coca tea is a nice change of pace from caffeine-based natural stimulants.
With respect to psilo(cy)bin, there's a product one can find sometimes called 'tootsie roll', which is a concentrate of the alkaloids mixed with chocolate and other confectionary ingredients. A simple alcohol extraction will do the trick, and ordinary acid-base workup can get whatever degree of purity is desired.
The phosphoryl group is somewhat delicate, which means what you end up with using acid-base is mostly psilocin. But no one actually cares about that ;)
From the article, apparently yes it can: "It's unfeasible and way too expensive to extract psilocybin from magic mushrooms"