Nothing about the merkle tree that blockchains are built on prevents you from truncating the chain in certain circumstances. The truncated piece can still be ve

Nothing about the merkle tree that blockchains are built on prevents you from truncating the chain in certain circumstances. The truncated piece can still be verified against an un-truncated chain for auditing purposes. So it would be possible for a smaller section of the network to keep the full chain while a larger segment of the network can keep truncated chains of a smaller size. You can configure the allowable size as well so any particular node on the network can decide how much of the chain they prefer to keep around.