[runeks]

> You only need to compromise 2-3 of the major mining pools and suddenly a 51% attack isn't so unfathomable, and that's just one potential attack vector.

If an attacker manages to gain control of 51% of the processing power, he can either a) choose to earn ~$350,000 per hour playing by the rules (mining to his own address) or b) perform a double spend attack on someone (in which case he needs to own over ~$350,000 and find someone willing to pay him in cash before either the mining pool or the network discovers the attack). Which will he realistically choose? The settlement time for USD is in the order of days. Will he risk a USD transfer being aborted before he can get his money, or play it safe and generate 12.5 bitcoins (~$100,000) within 20 minutes to his own address?

Also, exchanges and nodes can easily see that a fork is ongoing, with just barely half the hashing power on the honest chain. Chances are exchanges would shut down, clients would warn of a 51% attack, and the attacker would be left with the only option of mining honestly on the longest chain to his own address, thus taking money from poorly secured mining pools, but not affecting the stability of Bitcoin.

> What happens if a bitcoin core dev gets compromised?

I don’t know. What do you suggest would be the consequences of a single Bitcoin Core dev getting comprised? I highly doubt any code of his would even be merged into master, much less make it into a release.