Not everyone needs a full copy of the blockchain to run a node. A pruned full node downloads and validated all blocks, then discard everything not relevant to

Not everyone needs a full copy of the blockchain to run a node. A pruned full node downloads and validated all blocks, then discard everything not relevant to its own wallet. A variety of “light clients” are also available for most chains, which fetch transaction data from peers as needed (usually using something like bloom filters to increase privacy). Most ethereum apps just go through Infura. That’s a horrible centralized single point of failure that I’m not advocating, but the point is there are many ways a wallet app can connect to a remote full node.