I am confused by everyone's assumption that the 'early adopters' took a risk...pennies worth of electricity is not a risk on generating thousands of worthless bitcoins is not a gamble.
I don't think it's just the risk they took that entitles them to the gains, but the contribution that early-adopters make to the economy.
As I've mentioned before, there is no easy way to KNOW what the market will demand, and contributing to something that eventually does become valuable is a valuable contribution to the economy and should be rewarded.
Being in a position to discover a project early-on that turns out to be immensely valuable means having access to information that is generally valuable for society. It encourages people to spend more time reading up on new technology, for example, rather than following sports news.
Likewise, taking the initiative to get involved in something that ends up becoming very valuable, that most people did not bother to get involved in when it first came to their attention, is also a valuable contribution to society.
Investment gains reward the skills, insights and initiatives that people have in direct proportion to how valuable they are to society.
A meritocracy is a theoretical concept where everyone gets exactly what they deserve, based on merit alone. Currently, many do not get what they deserve because they find themselves in situations outside their control that limit their ability to move up the social ladder.
Government is not omniscient and is not able to know what role irresponsibility played in a person's poor circumstances rather than bad luck. Providing for the unlucky also means providing for the irresponsible, and this reduces the incentive to behave responsibly, leading to less prosperity overall.