Countless powerful people were forced to walk the path of the Ghost Immortal.
Without exception, their Physical Bodies were destroyed.
Although the River of Nether could submerge the damaged Physical Bodies of some powerful people at its bottom, the Physical Bodies of many more Ghost Immortals would disappear forever.
The corpses in the river are merely a manifestation of the Dao.
Of course, Ghost Immortals whose Physical Bodies were sunk at the bottom of the River of Nether would naturally find it easier to retrieve a Physical Body than those without any remains.
Returning to the Netherworld is about restoring the Ghost Immortal's foundation.
It's not truly about retrieving a Physical Body!
This principle, though simple, is a conclusion that Cultivators can only reach when they stand at a high vantage point and survey the entire path of Cultivation.