I would assume that soon, they will need to adjust it so that it will take only 10 minutes to process a block, despite how big the block size is. This is to synchronize with the satoshi's original coin supply time table so that by year 2140, the total supply will exhaust at 21m coins. In order to be profitable, the miners will need to be get majority of the reward from the transaction fees as the BCH value is only 6% of BTC. (They get 7 more times of transaction fees than BTC miners as their block is 8x bigger. This assumes that people are willing to pay similar fees for BCH as for BTC.)