Bitcoin value vs. Supercomputing What protects the stability of Bitcoin's value if supercomputers or some other technological breakthrough allows them to be mined at rates we have not anticipated?
The system is protected by an incentive mechanism. As Satoshi said in the paper itself:


  He ought to find it more profitable to play by the rules, such rules
  that favour him with more new coins than everyone else combined, than
  to undermine the system and the validity of his own wealth.


This means that if someone has access to a supercomputer, more powerful than the entire network combined, it would make more sense for them to use such computer to mine in a honest way and earn more reward than any other miner. Rather than actually use the power to do dishonest things, like to double-spend or to invalidate transactions, which would diminish the network's validity and therefore the value of the attacker's mining reward.

Also, if such computers are ever built, many people would want them, which would eventually redistribute the power. In that sense, ASICs could be considered tiny supercomputers.