This is my speculation but the government is slowly making a problem in the community until one point they are replaced by the government. The pseudonymous bitcoin maybe will not be so secure once it is controlled by bitcoin and maybe even we are not in control of our bitcoin like fiat money.
Looking back, the Mt. Gox problem is also worth to be wary about. The exchange company once marks the highest price in history of bitcoin was hacked. I mean if someone hack a exchange company there will sure be panic and price will decline sharply, even if someone want to sell it they need time to sell it and it disrupts the balance of bitcoin price. Why do hackers do that? Or there is another agenda is going on behind it?
If we see the graph of the price we will notice that there is a steady increase in price when the China opens for bitcoin and EU declares no VAT on bitcoin trades.
This is just my own personal opinion you can condemn me if I am wrong. Please be polite however, and try not to use vulgar words.
The hackers will exploit weaknesses in centralized services and they are driven for the monetary reward. The exchanges are the best target for these people, because large quantities of coins are stored on this systems. Until today, no hacker has hacked Bitcoin by encrypting the private key, and I doubt if it will ever be done, so they shift their attention to the things that can be hacked. < Exchanges >
Disclaimer : Some hackers < White Hats > will not exploit the vulnerabilities for monetary reward. < Stealing coins >