My guess is that a poorly encapsulated, communal gloop of organisms lost out to closely guarded species for the same reason that the Linux community didn't come up with the iPhone: Encapsulation serves a purpose. (discovermagazine.com)
When you do reach the Jaxi Ruins checkpoint, look down into the purple gloop swamp below and you'll see four coins spread across two islands. (eurogamer.net)
Here in the Lost Kingdom, a large majority of the 50 Regional Coins in this area are divided across lots of high platforms and over those deadly purple gloop swamps. (eurogamer.net)