The high fees of gwei in Ethereum transactions are due to the supply and demand dynamics of the network. When the network is congested, users need to pay higher fees to prioritize their transactions. The popularity of DeFi and NFTs has increased demand for Ethereum transactions, leading to higher fees.
it's not only due to Defi and NFT there are many factors out there and that included the emergence of newest layer 2 blockchain that also submit their batch transaction in ethereum blockchain.
moreover many airdrops claiming right now are requiring smart contract interaction unlike before where they just outright airdrops to some address but nowadays one need to interact first to get the airdrops they deserved which only means more congestion to the blockchain. there are many ways to increase efficiency in interacting with blockchain but many are still prefer some gimmicks so i'm sure this problem will be left unresolved for many years to come, that unless the developers of ethereum comes up with miraculous solution.