There are no known feasible attacks against the blockchain. Emphasis on feasible. Remember people have a direct monetary incentive to hack it (millions of dollars) and yet it has stood the test of time.
In my mind, correspondingly, there has been a direct incentive to subvert this from the powers that be, and it has also stood the test of time.
You could take a third way approach and say that there is an incentive to hack and subvert from within blockchain miners/verifiers, etc, but again, each party that has an incentive, the other party has a counterincentive.
The entire thing is really brilliant in the way it balances incentives and directly leverages money to do so for parties that wouldn't otherwise care.
tl;dr they didn't hack the blockchain