That's an interesting point. But I can't get if your are talking about the price or the "adoption", i mean: a speculator "adopts" bitcoins iff he buys them once, it doesn't matter if he sells them after. And that should be S shaped.
Also "hoarding function" should be S shaped, where hoarding means truly belive in long term prospects of bitcoin and do not sell under a very high price.
We need a model of demand/supply, given this two S shaped extremes. Just thinking loudly.
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sorry, but if you are pointing there on a non constant regression line (like rpitelia's) this, i think, does not affect the overall s shaped quality of the curve... I'm a newbie here so i like to share thoughts. Very interesting matter, indeed.
Read again. That was not the point. Speculators need to move to the best investment as price of BTC peaks. Read that part.
This:
Lets look at it psychologically. When the BTC price stops rising because the capital that can and will be moved into Bitcoin has slowed (or peaked), then those who own $100,000 to $millions (which probably includes all those who own $10,000+ of BTC now) are going to want to deploy their capital productively. Unless Bitcoin is as widely accepted as the dollar, then they will find their opportunities to invest BTC in businesses without it being converted to dollars will be limited and it will prevent them from optimizing their investments.
So capital will leave BTC to the point that each person holds in BTC what is reasonable for the opportunities of medium-of-exchange that are available. Since BTC price is rising so fast, we are looking at market cap saturation no latter than 2016 ($1m per BTC x 15m coins = $15 trillion) unless the general public is selling assets to buy Bitcoin, but more likely 2014 or 2015. That is not enough time to develop a wide enough medium-of-exchange ecosystem.
Also,
Bitcoin has no utility (except perhaps as the government coin).