The assumption of bitcoin going to 1M is too optimistic. The fundamental and market usage for bitcoin might be strong, but I do not see how this correlated to price going upward. Remember, 100 usd per coin or 1000 usd per coin doesn't change how the protocol work.
It does not affect the protocol, but price (and therefore market capitalization) makes a difference in the economic viability of a currency. For example, if a bitcoin were still worth $1, it would be impossible to buy a moderately luxurious estate such as this using BTC:
http://www.zillow.com/homedetails/%28undisclosed-Address%29-Beverly-Hills-CA-90210/2105605053_zpid/(only a bit over 13 million BTC have been mined until now).
As soon as transactions regarding houses, cars, ships, or planes using bitcoins become common, a single bitcoin must be worth much more than $10,000. $1M isn't really far off.
Of course, this assumes that bitcoin is the only or at least the major cryptocurrency in use. Unlike gold, which can't really be replaced by anything else, bitcoin could just be replaced or supplemented by other crypto currencies.
Onkel Paul