If I'm reading and understanding correctly, it looks like Ethereum's blockchain is 18TB, but you only need to download about 1.1TB if pruning: https://eips.ethereum.org/EIPS/eip-4444
It's not actually pruning, the full node is really around 1TB. That 18TB number comes from old naive design for an archive node. Archive is basically cached state after each historical block. The 1.1tb full node can generate all this data by executing blocks and the current generation of archive nodes can store it around 3TB instead of 18TB.