I'll admit that gmaxwell brought up some potential issues I hadn't considered. Most of the centralization alarmists have painted a less nuanced picture, leading me to think economics and incentives were being ignored. With that consideration understood, becoin is correct in saying that despite this natural order or free market being able to adapt, the time frame for adaptation matters. If miners don't detect a problem in a matter of minutes, Bitcoin could possibly suffer a major setback and PR fiasco. The market would adapt, but its solution might put a damper on Bitcoin growth for a few years, or the market's solution might even be a (good) protocol change or a new coin.
Nevertheless, the question remains: why would bad acters refuse to take advantage of vulnerabilities as the ongoing centralization makes them available? Why would they hold off their attacks until Bitcoin is so centralized that they could do extreme damage, especially given only one criminal gets only one shot? Every incentive seems to point to being the first to exploit a centralization weakness, which should lead to a smaller issue, or at worst a series of smaller issues that would make miners steadily more wary of large mining pools. Why aren't these supposed weaknesses being exploited right now? Hackers don't seem to generally shy away from taking free money, even if the stakes aren't yet as high as they could be.
Ultimately there needs to be a reason why a bad acter would choose not to "get while the getting's good," and in so doing actually do Bitcoin a favor by waking people up to any actual vulnerabilities as they arise. Centralization is a gradual process, so why wouldn't vulnerabilities open up (and be exploited) gradually rather than suddenly and catastrophically? Only a government or other entity wishing to do damage to Bitcoin (a competing system or altcoin, etc.) would have the right incentives to wait.
this is the dynamic "tension" that exists in Bitcoin. since there is no CEO you can call up to ask questions or try to manipulate for inside information, we find ourselves constantly evaluating the technology itself. this is difficult b/c we are dealing something none of us has ever seen before so we find ourselves injecting our own personal biases into how we look at the situation.
i am not saying bury our heads under the sand and ignore what potentially could be centralizing factors. we always have to live on the edge and assume bad things. but at the same time i do not share gmaxwell's concerns as to where we are now in the evolution of they system. i remember having a conversation with theymos way back in Jan 2011 when he predicted we'd be where we are now with a few thousand listening nodes. now, just b/c he predicted it doesn't mean we are in a safe situation. the point is that many of us from the early beginnings thought this would happen yet this didn't scare us into participating and helping to build Bitcoin to where it is now. the question is, has this "centralization" weakened or in fact strengthened Bitcoin?
it's too early to say but i don't think it has weakened the system. gmax keeps saying someone could hack into BTCGuild and cause havoc right now. well, as Zangle has pointed out, why haven't they done it yet if it's so easy? i think it's b/c the pool operators are all over security as much as they can be. look how fast everyone responded to the hard fork; within minutes. they have the capacity to cut off an attack immediately if one occurs. gmax, i don't think you gave a full characterization of the motivations behind what happened either as i read the IRC transcripts from that event very carefully. Eleuthria was never promised to be paid back as a quid pro quo for his cancellation of the 25 blocks he mined on 0.8. from what i've read, he "voluntarily" did what was right for the community as a whole first and then was only "reimbursed" by Gavin from his personal faucet (or something like that) much later after the resolution of the fork. there is a big difference in the interpretations of Eleuthria's motivation btwn this and what you implied.
i also wonder why the top 250 addresses haven't been hacked yet if there truly were a fault in the ECDSA system. i don't buy the supposition that an attacker is waiting for a more opportune time. there would be no point in doing so especially as the hashrate and network continues to strengthen in what is a parabolic fashion. if anything the alarm bells should be ringing full on in NSA if their underlying motivation is to eventually destroy Bitcoin. same thing goes for any attacker that might try to co-opt the pools. the best time, in fact, was over a year ago when the network was much weaker. and as for collusion btwn the pool operators? ain't gonna happen. it would've happened long ago. we all know that slush, Eleuthria, and Deepbit are hard core Bitcoin supporters. they won't do anything to damage Bitcoin and a collusion to inflate would be just the thing they would seek to avoid. on top of that, Deepbit is known to be a lone wolf and does what he wants to do. as i recall, he was still running some pool software based off of 0.3.* (very old) when the hard fork hit and was one of the ones left behind old 0.7 chain as the miners went off on 0.8. why would he do that? it's b/c he is happy with the system as it stands, ie, decentralized. why change
anything if it's working out well?