I'm new to blockchains so I'm sorry if this is stupid, maybe somebody can explain to me.
Why do everybody needs to keep everything? The chain will be much smaller with just the id and the hash of the block. The payloads could be kept only by the interested parties and could be validated when needed with the chain.
Because every node in the network must be able to verify all transactions all the way from the genesis block. In order to ensure that this is possible, everyone who keeps the history must keep the full history.
With the MimbleWimble design [1] [2], inputs may be cancelled against the outputs they spend, with no loss of security. Essentially, the entire blockchain history may be collapsed to a single mega transaction, with all coinbases as inputs and the UTXO set as outputs.
