I happen to think we can do better than Gavin's idea. I like the idea of trying to come up with a solution that works with the blockchain and adapts over time instead of relying on Gavin, or NL or whomever. The answer should be in the blockchain.
The answer cannot be in the blockchain, because the problem being addressed (resource usage rising too quickly so only people willing to spend tens of thousands of dollars can participate as fully validating nodes) is outside the blockchain.
You will go down the same path as the proof-of-stake folks, coming up with ever more complicated on-blockchain solutions to a problem that fundamentally involves something that is happening outside the blockchain. In this case, real-world CPU and bandwidth growth. In the POS case, proof that some kind of real-world effort was performed.
Thank you for your contribution and criticism.
Since the difficulty adjustment already effectively assesses real-world CPU growth, I'm unready to assume impossibility of real-world assessment with respect to bandwidth, as there are evidence of both in the block chain awaiting our use.
Analogies to PoS are also no proof of a negative.
They answer may be in the block chain, and it seems the best place to look, as the block chain will be there in the future providing evidence of bandwidth usage if we can avoid breaking Bitcoin protocol today.
I don't need anyone to be right or wrong here so long as in the end we get the best result for Bitcoin. I am very happy to be wrong if that means an improvement can be made.
Gavin, I remain grateful for your raising the issue publicly, and for keeping engaged in the discussion. I do not agree that discussion on the matter ought end, and think we can do better through continuing.
Wherever we can squeeze out arbitrary human decision through math and measurement, it is our duty to the future to do so. The alternative is to commit our progeny to the whims and discretion of whomever is in authority in the decades to come. As David Rabahy pointed out a few posts ago, we may not be pleased with that result.