Yes, the costs are the same. The likelihood is what the argument is. It may be slightly more likely to construct an attack with GPUs, but that effect is basically entirely washed out by the relative market cap of the respect chains. 51% against ETH is way less likely than against Grin or ETC, just due to the difficulty. The strongest chain (with a particular PoW algo) always wins.
I would argue that the “self-interest” of GPU miners is known, as they are the incumbents, so it’s a sort of “prefer the devil you know to the devil you don’t” conundrum. The “status quo” would allow a relatively unknown actor into the Ethereum community, with a more complex and possibly counter-active set of incentives, which is more likely to be exploited due to the central power of that actor and cause network disruption at key points. We can point to Bitmain as an example of this.
The parties you mentioned are well-known members of the community, and if that’s all you need to be convinced I suggest you take a closer look at their arguments instead of just relying on their reputations.
To my knowledge, the most interesting and helpful argument that could be construed to be against ProgPoW is from Phil Daian. That post is here:
His conclusions are simple: PoW have inherent economies of scale built in, which are impossible to remove. PoS is the only potential mitigation for these faults. Working on “anti-ASIC” PoW algorithms is thus a waste of time for anything but a short-term gain.
I don’t want to put words in Phil’s mouth, as I respect him and his work very much, but I don’t think he would consider himself a hardware expert. His research is primary in code security and smart contract development, although he has a wealth of experience and observations that would be foolish not to take into consideration. At the core of his argument is this point: “anti-ASIC” PoW algo changes are a waste of time as a long-term solution.
ProgPoW is not intended as a long-term solution. It is intended as a 1-2 year stop-gap measure that should even the economies of scale between ASIC manufacturers and GPU miners (who mine with commodity hardware). It is used to help us get to PoS or a Hybrid PoW/PoS option, which will be possible in about 1-2 years when we are confident in the operation of the Phase 0 Beacon chain.
You can make up your own opinion with this information, but I think you know mine. I respect your right to have a different opinion in this regard.
The rest of the people mentioned, to the best of my knowledge, have one or more of the following arguments:
- Phil’s point on anti-ASIC algo changes (we discussed this above)
- “It’s a waste of precious developer time” / “It’s a distraction from ETH 2.0 / PoS schedule” (most work is done)
- “It’s contentious, therefore we shouldn’t do it” (circular argument)
Please correct me if I’m wrong, but these are the only arguments I have received from these prominent community members.
To address 2) Most of the work is already done. The rest of the work is planned because enough people want to see it happen. The teams involved are largely completely different. The only real distraction is the involvement of this proposal into a scheduled hardfork, which considering this EIP is the most complete of any proposed for Istanbul isn’t really a great argument.
To address 3) This is a circular argument. “Contentious” means people disagree. If they disagreed for technical reasons, we should answer those concerns and resolve them, absolutely. If they disagreed because they have a different viewpoint (such as Phil’s conclusions), then we can debate and come to consensus on which way is best for the network. I am very open to this. If they disagreed because other people disagreed, because other people disagreed, then we are all participating in a circular argument, wasting people’s time, mental health, and “social capital” by continuing to debate this important change.
Since proponents believe strongly that this makes the network better, and detractors have few if any real arguments against it (besides the fact they don’t like it), I would suggest that the onus is on the detractors to raise technical concerns (to make the proposal as robust as possible, or show an un-fixable flaw), or to help come to consensus on these less fact-based arguments and opinions that are difficult to resolve so we can put this issue to bed. We currently have no forum for doing this sort of discussion, at least none that resolve with any real certainty, so this is a difficult thing to do. But I would argue that if we cannot do this (discuss and resolve contentious issues like ProgPoW) with any sort of final certainty, we will be royally fucked when more complicated proposals come though. This proposal is fairly straightforward, and good opportunity to experiment with solutions for this critical problem. (Hint: no other blockchain project have solved this either)