HyPC is required to set up a Node Factory, it is converted to cHyPC on mainnet and functions in the node factory to facilitate the split of nodes and is technically how 1 node can become 1024 nodes in 6-8 years. 

The conversion that occurs (HyPC>cHyPC) has to be reversable to account for human error etc. in set up.

It is extremely unlikely a user would dismantle a Node Factory and put the HyPC back into circulation, as a whole Node Factory will have significantly more value than the sum of its parts.

It is extremely likely that 0 HyPC will be in circulation in the end, all HyPC is destined for  mainnet in order to scale to meet the demand of AI compute.