...with only 500K-2M users as per Bitcoin.
Those numbers are overestimates, the real numbers are closer to 50k-200k.
Then that would be more incentive for people to roll up their sleeves and grow the userbase. Bitcoin after all had a peak capitalization of what $18 billion or was it higher?
The commodity characteristics means if any digital currency were to hit 100 million users then it would be probably be worth $Trillions.