Consider a price spike from 1 USD to 3 USD in a token that trades on an on-chain automated market maker ... A miner performing a time-bandit attack can now rewrite history such that it is on the buy side of every trade, accruing a substantial balance in such a token at below market rate—before the price spike.7

For example, if the attacker wishes to rewrite 24 hours of history, and 1M USD of volume occurred in exchanges with rewritable history in that token, then the attacker can obtain a MEV gross profit of 1 M × (3 USD - 1 USD) = 2M USD.8

At the time of writing (March 2019), http://crypto51.app/ estimates a 24-hour 51% rental-attack cost on Ethereum of about 1.78M USD, implying a net profit of around 220K USD.