I agree with that the utility and demand is critical to the value of a crypto-currency. That is why LibreFortune regards both designing a reliable PoS protocol and building an open app platform as its core missions.

As for a price floor, even in PoW, a miner mined coins at 100$/coin does not mean he won't sell it at a price below 100$/coin, although he's unwilling to. Actually for PoS, the reluctance to sell (due to high relative mining rewards and virtually no mining cost) is more worrisome. And that is why we adopt a three-year multi-stage distribution plan.

In a PoS system with fair mining, by mining a miner gains more coins, but the percentage of all coins owned by the miner doesn't increase. But stop mining will cause forfeiting mining rewards. Thus PoS mining reward can be seen as an incentive to NOT stop mining.