If there is increased demand then the price will inevitably go up but this creates speculation and hoarding. This means that there is very little incentive to actually spend Bitcoin to pay for goods.
from what i understand, the idea is that the demand will increase but get to a point where it stays the same, eg. reaching mass adoption. when demand is not rising and supply is fixed the price should be a lot more stable.
we are currently on the foot of the adoption S curve that is why the volatility is high and the rises are this big.
If there is a decrease in demand then the block reward will decrease to move the price within the desired equilibrium.
the block reward is creating
new supply not controlling all the supply. so if you decrease or even make it zero or 10 million you still have to consider the existing circulating supply. for example if your coin at some point has 100 million coins circulating whether your new blocks reward the miners nothing or a lot doesn't change much.
additionally if the reward is like bitcoin's, the miners can not sell their coins until they are matured meaning 100 blocks should pass (IIRC). and that takes time so your block reward adjustment may not even be able to affect the market that fast and this maturation time is needed to control the flow too.
The idea is to factor in the delta of transactions, addresses, and volume in a given period of time into the algorithm by using a weighted scale.
i don't think any of this data can be trusted and it doesn't need a spam attack to change it. because all of it depends on how price is moving. if there is either a surge up or a drop down there will be a lot of transactions, a lot of addresses used, and the volume will go up.
1. Well demand will never reach an equilibrium even under the insane idea that there is 100% adoption. There is nothing to bridge the gap there but even if there was population numbers do not stay the same so thus demand will inevitable rise even under the best of circumstances.
2. You are correct but my algorithm would have no limits as to how high the block reward could rise or how low it could fall. Basically, regardless it should be able to adjust to any market conditions and it would absolutely dissuade people from trying to speculate. I am ok with it not having a perfectly immediate affect though since I am not trying to maintain perfect stability but rather relative stability within a range. I am not naive enough to think perfect stability is attainable.
3. Well I don't know if you are making my case for me or not on this one. That is literally at the core of my idea. When was speculation most rampant and price movements most severe in the past year? Well December speculation rose and thus transaction levels rose. My algo should theoretically work to dissuade this activity.
My main weakness, in my opinion, is actually probably on the miner side rather than feasibly being able to stabilize price. With there being not a lot of pressure pushing price upwards there would naturally be an equilibrium as far as mining goes as well. Of course I need to think of more of the angles still since the idea and even the algo itself is in its infancy. Of course this theoretical coin would retain many of the other properties of Bitcoin and other crpytos in general.