the transaction fee is a sort of service fee from the miners and the witness signer of the the ledger from the blockchain in order to secure your transaction free from hacks and tampering. adding security features of bitcoin takes a lot of cost. If you want sort it out like verification is thru phone or any devices nearby that are bitcoin users are the one who verifies your transaction without the need of miners signatures on the blockchain, that's is what we called off-chain verification. Lightning Network trying to proposed this kind of solution to reduce transaction fees and speed up transaction capacity per second,the only problem is it needs another centralized network or server that need to broadcast or sending the data back to the mining pool and acknowledges the miner that those transactions were verified from the mobile devices but it does violates the bitcoin protocol of decentralization, an off-chain verification is possible but it can be a different entity not related to bitcoin mining.