Proof-of-Stake (PoS) inhibiting circulation, cryptoeconomics

Sorry if this has been asked before, but I just couldn't find a thread discussing this.

If you're staking money, you're not spending it. Spending money instead of saving it, has been probably the greatest economic dogma for growth, which is also why, most economists would opt for (low) inflation, just have a look at what central banks are doing all the time. Now if everyone is trying to stake in order to gain interest rates (Vitalik mentioned some percent p.a.), what could the effects on the supply effectly be and could it inhibit the dynamics of the whole platform as such?