(I think I can help clarify this and will be corrected if I err at all, I hope. The system docs are good and getting better but the system is so intricate that a lot of ins and outs are fleshed out through various threads on the forum. Also, final decisions as to exactly how things will work are being made along the way. Your summary is really kickass over all.)
I’m pretty sure the following is solid and won’t change:
Neither PUT or GET are a one-for-one cost or reward.
On the PUT side: One safecoin will cover a certain amount of data PUT by a particular user (like 1 safecoin for x number of megabytes PUT/stored to the network). This resource is purchased from the network at large. The amount of storage one safecooin will buy will certainly rise over time.
On the GET side: Successfully executed GETs will give the farmer the opportunity to request safecoin, which will be awarded on sort of a lottery basis. So not every GET fulfillment will result in an earned safecoin. More safecoin are available early in the network’s running and so will be easier to farm at first. The odds per request will be better. Over time they will get harder. Vault rank also factors in somehow.
Safecoin paid to the network for the ability to PUT data will be taken out of circulation and made available for refarming. Thus safecoin will act as a continual lubricant, even after all the original safecoin have been farmed. As safecoin gets more valuable it will buy more resources, so less will be recycled. This will have the effect of farmable safecoin continually getting rarer, and more valuable. But there will always be some there to farm. Pretty slick.
It’s hard to imagine how such a decentralized network can manage to be fair in all this, but David Irvine has been pretty convincing that it can. Every now and then a new “Ah-Ha!” knocks me on my rear.