One of several great things about 100% PoW is that it isn't ideal as a scam/ponzi/P&D coin because distribution is open to anyone doing the work, is expensive and any weak PoW currencies who don't capture the interest of the public with true innovation quickly get attacked because they don't have the mining hashrate to sustain against an aggressor.
You can easily spot a scammy PoW coin by it having a extremely sharp rather than gradual distribution curve - I.E... Quark.
It seems to me that (unlike PoS) PoW must be a ponzi scheme or ever-inflating, otherwise it will be unsustainable.
PoW is not a ponzi, if you have any understanding how PoW works then you will know this is the case.
PoW will only be inflating until all of the units have been received via the block subsidies at which point the miners will receive block rewards from TX fees, which is the same how PoS coins reward their "miners"