I’ve said it before and I’ll say it again: transaction fees are not an anti-DoS measure. We’ve never claimed that that’s their purpose or that they could be effective as such. It wouldn’t be a vulnerability if transaction fees were zero, except to the extent that miners wouldn’t be incentivized to include transactions.
The primary anti-DoS measures in Zcash are the block size and (for the mempool) ZIP 401. Our intention is that the worst-case resource usage for a block still allows it to be processed in a small fraction of the average block time. Whenever that has come anywhere near not being the case, we’ve made changes to fix it (e.g. limiting the number of inputs before Overwinter, the consensus change in Overwinter to fix quadratic hashing, and improvements to Orchard verification that will be in zcashd v5.1.0 and zebra 1.0.0-beta.12).
If other anti-DoS measures are needed in future, we’ll add them.
Here’s why that is wrong: the “almost” is precisely the case you need to worry about. DoS attackers can pay more than legitimate users are prepared to pay overall, because they usually have motivations that are not directly monetary. If you increase transaction fees then you’re putting an obstacle in the way of adoption without fixing the underlying problem. The way to fix this in the long term is to massively increase chain capacity by reducing how much needs to be put on chain.
No. I cannot help someone speculating about what I’m paid or should be paid in public messages. But a message to them if they care about my opinion at all: cut it out.
[Edit: there haven’t been any transactions using either of the two vanity addresses mentioned since 10th June, anyway. Those transactions were fully transparent and I’m not aware of any evidence that they are related to the Orchard ones that were filling blocks, or the later Sapling ones.]