While in PoS or hybrid PoS chains where there is no connection to physical energy the clones needs much less resources in order to gain "security" and decentralization: it is far more easier to build a network of people incentivized by massive gains than to build a network of miners collecting energy.
In this way PoS currencies are much like fiat currencies! Even if a single PoS chain cannot inflate its supply, its forks with more incentives are going eventually to indirectly inflate it.