arhag's (currently #1 ranked) post summarizes some of the thinking, and also I'd suggest my comment there for a bit of elaboration. In essence Steem Power is a prepaid subscription to network access. By stocking up on Steem Power now you are speculating that access to the network will be worth more to more people in the future, who will then be clamoring to buy tiny slices of your Steem Power to get in or to maintain their access. Obviously, that is a very risky bet (all cryptos are, including Bitcoin).
https://steemit.com/steem/@arhag/where-does-the-money-come-from-a-look-into-the-economics-of-steem
You are basically going long for 2 years... in a crypto currency.
Seems extremely stupid to me.
Average of one year, assuming you start liquidating right away, but still, I agree, it is a very risky bet.
Price weighted average, but you wouldn't be able to decide when to sell. You'd be pre-deciding to sell early (or late).
You can sell your account too, probably at a reduced rate (though it would depend on your standing in the community).
@smooth, how long do curator's get payment on posts? Just want to know if that figures into the analysis.
I'd love to see a market for selling accounts develop. But since you can't transfer SP, then it means you really can't sell them in a secure way. So no such liquid market will develop. You basically have to trust someone to let them have your account and change the password. Someone has to go first and take all the risk. I suppose you could do it with trusted escrow.
Curation income is not worth anyone's time at only 3.875% of their holdings per year.
Edit: Thinking more about this. The price paid to cash out early will be a function of the volatility. We know this from the pricing of futures markets. The higher the volatility, the lower the price the seller will receive. Also there will need to be some time-weighted factor of blackswan computed by the buyer. The seller will pay in advance for 1 year of risk in terms of lower selling price.