The lower Gas costs brought by the Cancun upgrade are indeed satisfying, but there's an easily overlooked detail: the Blob data of EIP-4844 is automatically cleaned up after only 18 days on nodes. This may sound trivial, but in reality, it's quite critical—years later, trying to retrieve the history of a certain Layer2 transaction could become an impossible task.

From a technical perspective, Ethereum has its reasons for doing this: reducing node burden and lowering storage pressure. But at what cost? The complete ledger history of Layer2 is passively weakened. If we say "decentralized accounting" and can't even access data from three years ago, that’s indeed a bit embarrassing.

The logic here is quite clear: the mainnet can't handle all historical data, so someone has to take over. A feasible approach is to use trustless cross-chain mechanisms to automatically transfer soon-to-expire Blob data to dedicated data storage layers, forming a layered architecture of "hot data on Ethereum, cold data stored off-site." This way, Layer2 can enjoy the security guarantees of the mainnet without weakening verifiability due to data loss.

Ultimately, Layer2's claim of "secure and decentralized" must be backed by a complete, traceable historical ledger. The design of data storage directly affects the trustworthiness of the entire ecosystem.