Koryu's interpretation is correct. The price is calculated simply as (#users X AvgHoldings)/#Coins. I actually used 12 million coins because rounding and lost coins.

Oda, the 12 million number is the estimated number of coins (not number of users). This chart contains no data other than the number of coins in circulation, which is actually an upper limit. I do not assume a normal distribution in making the chart. I mentioned that just because interpreting a mean is somewhat non intuitive for the extremely skewed distribution that probably describes bitcoin holdings per user. However it is still valid to calculate the mean and use it as a summary statistic.

I found the chart interesting because it is an intuitive way of showing the dependance of price on the number of users, wealth of those users, and their sentiment towards bitcoin. Even though the chart shows the mean, and the mean can be unintuitive when describing a skewed distribution, we also know that the mean cannot be less than the minimum.

So the way I looked at that chart is to ask "Is it plausible that there are 2,000,000 people out there willing to store at least $4k of value in bitcoin?" If that many people are willing to store at least that amount of value, some will be willing to store more and thus the users will be able to support an even higher price. I think that this is plausible and so the current price of $600 is not insane or anything like that.

I have no data for this however and was hoping others had estimates of users and average btc wealth.