That is a good observation that most of the historical data does not need to be kept around. I believe what you are suggested is already implemented, however. Bitcoin Core can operate in a pruned mode, where the bulk of the historical block data is discarded and only the current UTXO set (and a few recent blocks) are kept. As you note, some nodes on the network need to run in archive mode to help new nodes get in sync. BIP 159 helps identify these archive nodes at the gossip layer.
In the case of lightning, some implementations made use of the additional txindex, which is not compatible with pruned mode.