ETH gas fees have been reduced almost 50% due to flash bots.

Gas fees on Ethereum blockchain have reduced by almost 50% due to adoption of flashbots by traders in place of PGA bots. In the last 24 hours, the average gas fees for transactions has come down from around 120 gwei to around 65 gwei currently.

Right now over 58% of the hashrate is achieved on flashbots and PGA bots seem no longer able to compete. PGA bots usage increases the fees paid by Ethereum users while flashbots reduce it. As flashbots gain larger share of hash rate then gas prices should continue dropping.

PGA means Priority Gas Auction. It’s when arbitrage bots monitor their competitors transactions and keep bidding up the gas against each other. While the traders can get their transaction higher up in their priority list, this keeps the gas fees on mainnet up high arbitrarily.

Here is a paper on gas fees mechanics in a decentralised ecosystem: https://arxiv.org/abs/1904.05234