Blockchain's Dirty Secret , It’s Not Forever, Immutability != Permanency

Blockchain immutability, meaning recorded data cannot be altered, does not guarantee that the data will remain permanently existent or accessible. The article says permanency depends on protocol evolution, data archiving strategies and economic incentives for node operators. It cites Solana's move to archive its historical data on Filecoin, replacing Google BigTable, which the Solana Foundation had used with gated access, and notes that Filecoin uses rental contracts rather than one-time payments, so data may not be kept if the owner stops paying for storage.