The issue is that ETH only can handle a certain amount of transactions per block (based on its block size). When the network gets overloaded, all of the potenti

The issue is that ETH only can handle a certain amount of transactions per block (based on its block size). When the network gets overloaded, all of the potential transactions cannot be held in a single block and must be delayed until the next block, leading to higher fees for each transaction, giving it a higher priority and making it more likely to put in a block of a certain size. Same 'problem' as bitcoin; too many transactions are being fit into a finite space per block increasing competition to have your transaction in a block, but really it's just basic scarcity economics.