Understood, wow, that's quite demanding, particularly for people running wallets on mobile devices. How do applications like Breadwallet manage to deal with all this data on an iPhone, for example?
They dont, breadwallet is not a full node. Most wallets are not, they rely on others running full nodes to get the data they need. I dont know exactly how breadwallet works, but common ways are either special servers (e.g. Electrum) that run a full node or directly query full nodes for data (e.g. multibit).