response to "biggest blocker" on eip-4444 ama: question: from `HarryZKE` --- I don't think the biggest challenges are technical following the roadmap of EIP-4444. Clients today already implement some form of pruning so it is not a big ask to extend this mechanism to more types of data a node already manages. The bigger challenge will be coordinating around the guarantees the protocol provides for history on the network and how expired history will still be accessible if something along these lines is deployed. In an ideal world, there will be several high-quality sources for historic Ethereum data, just like the role the Internet Archive intends to serve for Internet data. And moreover, these sources would provide this data for free, acting altruistically, even if only as a token of good faith to support other for-profit endeavors they undertake. While this may sounds like a lot of load to put on a few players, the Ethereum community can lighten the burden with mechanisms like Bittorrent so that only a few "bridge" nodes are needed to have a highly-available swarm of peers providing the data to whoever needs it. And if it becomes necessary, we can brainstorm further incentivization schemes like those used by Graph and others to index the protocol history.