STEEM POWER accumulates itself everyday, just by holding it, why is that ? Because if you power down you will hurt the economy of SteemIt, the only reason to power down is to have STEEM currency and sell it on the market to have real cash.
The admins of this system thought about it for a while, and they found the brillant idea to limit the power down ability to 1% per 7 days, so you won't cash out all your money at once.
What is the problem here ? Don't you see it ? Accumulating STEEM POWER from holding it should come from somewhere... this somewhere is the "central bank" of STEEM, created out of thin air, more money is created and injected into the system. Hyper inflation occurs, Hyper devaluation occurs, sounds complicated ? Let me explain, you have more money that is worth much less, just like the dollar, but on ectasy ! A hell of a ride to hyper inflation.
To be clear for those who don't understand complicated terms : You think that you wallet is growing everyday, yes, you have more STEEM POWER, but that POWER is worth much less every single day. 1 million coins will be worth the same as 10 coins today in the future.
While all of this happens, the value of STEEM is maintained artificially at high levels so the population of SteemIt won't panic and sell their coins and collapse the economy. Yes, that is why there was an incentive for trades and liquidity, because they need transactions, they need to make this illusion look real.
STEEM POWER lose value everyday, you have more of something that's less valuable. And the value can drop much faster when people realize this.
One day you will wake up to find out your STEEM is worth next to nothing.