As you have stated, price is not just a function of amount of oil. So, price does not define Peak Oil. Just being at the Peak does. As someone else stated, there is ALOT of oil at the peak, then it declines.
Maybe I will try to find correct data, but we DID hit and pass Peak Oil production in the US ( regular oil, not tight oil) when the prices got high enough, we have gone to developing non-standard sources. Since we can also alter how quickly we pump out, we may use it quicker or slower, but those fields we have going in the world, how much is available is at or near the peak. Obviously, it is a finite resource. The regular, easy to get oil did peak as predicted, or very close to it.
It makes a very big difference to the overall economy if it costs EROI 10:1 vs 3:1 (for example, I do not have ratios in front of me) Oil will not go away, it will get very expensive before that.
So, yes, we can get oil, we can predict it, but the easy stuff peaked and the stuff we can get will continue to have worse and worse EROI.
If something was going to be an even bell curve, it would follow that at peak you have used half, not all, not 80%, but half. Things are not even, it is hard to predict how steep or not the downward curve is how fast we use up the other half.
One of the things peak oil emphasies is how disruptive to common people the economies of oil decline is and will be. ANd, here there gets speculation of course, how soon will the decline (in the ground) translate to decline of available to use (as these are 2 very different things) ? How much and how soon will common people be disrupted by the economy that results from high prices of oil and job losses from changing economic picture ?
We know that we already have a very high real unemployment ( aged 18-64 non-disabled adults not in work force)
Ironically, the other peak prosperity linked article from this morning said they are moving to more automation in drilling and oil production, which of course keeps the price lower, so they can develope a bit more of the hard to get stuff in teh US at a price that they can potentially sell it at -- but then, more unemployment !