People who sell runs will still sell runs, and it's gonna be even more expensive because it'll be literally an exchange of gil for myth. You save 900 myth (and philo) and get a iLv90 weapon that will last you until Turn 5.

Remember people who buy Titan HM isn't buying because they want to farm it, they're buying because they want the Relic. It was never about farming anyway. Nerfing hard modes will indirectly promote selling extreme modes because it becomes easier to pug the hard modes.

People buy runs for three reasons: 1. they have the money lying around; 2. they cannot get a party together; 3. they simply can't do it properly. None of these three reasons are related to farming the runs. People who don't buy nor sell runs will do it once and never touch it, perhaps only do it again to help out buddies; people who sell it will still sell; people who buy it will still buy.