for POS, everyone can stake. In order to prevent hyper inflation (too many coins minted per day), you HAVE to have a low stake rate. Anything high will instantly lend to hyperinflation and making the coin worthless over time.
The better the rate, the more people stake. Since staking is like interest, you start to have compound interest and the minted coins per day rate gets insane.
Agree. PoS entry level is greater than PoW itself. Anyone can become a staker with the required amount of coins to stake, in contrast to PoW which requires costly equipment and daily maintenance. Minting coins with PoS is energy efficient and allows an average Joe to participate in maintaining the security of the cryptocurrency's network. While coins with high interest rates are most likely to experience devaluation and hyperinflation over time, they'll experience a higher level of demand than most PoW coins out there.
Of course, if you're looking into a PoS coin which retains its value over time, then you would need to seek a coin that has low stake rates. Coins like Peercoin, Blackcoin, and Emercoin have low stake rates, allowing them to maintain their value over time. As a suggestion, if you want to increase your chances of earning stakes on your coin balances, then you should use the Coin Control feature available in most PoS coins for optimum results. I believe that the future of mining lies on PoS, leaving PoW in the dust. Just my opinion