It does work though, which makes it clear that consciousness is a property produced by a mechanism in the brain.
Pansychism says that everything manifests qualia, not that you can’t change what kind of qualia with drugs — obviously you can, as anyone who has taken recreational ones knows. You can also change it with a bullet, though that doesn’t revert after.
The idea is that there's always "something that it's like to be X", where X can equally be a conscious human, an anesthetized human, a dead human, or an electron.
On the other hand, brains certainly do seem to function like qualia detectors (as evidenced by everyone talking about qualia). So, who knows, maybe there's something further to be explored there; maybe it's related to the combination problem (https://en.wikipedia.org/wiki/Panpsychism#Combination_proble...).
The idea that this makes it unviable is called Logical Positivism. Personally, I think Logical Positivism is short-sighted and uncomfortable with ambiguity. But that's more of an aesthetic preference than a scientific assertion.