The bounty missions do not stop, with such a high control value. And in these missions all enemies except the bounty target are capturable and in the high level quests, there are usually quiet a few enemies. So you should still be able to get up to 4 captures per day.
And then again, what did you expect would happen with a high control value, when your focus as a faction is "mercenary" (and you are harvesting bandits)? You have to make sure, that you do get a steady source of new bandits and not deplete them. High prosperity values and high corruption values (or low ones) are fine, but a not too high control value is important, to get a steady new stream of targets. Of course with a high control value you can always repent and purchase a lot of letters of indulgence for 100k, 10 coilguns or 25 automatic rifles per letter from the bandits headquarter.
And the best control value - in my unholy opinion - is between 25 and 30 control. Hint: With less than 30 control, you can get enemies in Whitehaven and Cole's Canyon, eventhough you might want to not garrison the Watchtower (after taking it), as that can increase control and hinders the bandits from setting up camp in Cole's canyon (or setting up a toll-booth in Cole's Canyon).
And for a low control value it is also important, to not have too many guards in your household (or better to not have a too high guardpower).
And you might also want to not always clear a whole bandit fort on the day the bandits take it, but let one group alive (as there are conclude day events, that can only happen, if the fort is still in bandit control and depending on the bandit-controlled fort, there are conclude day events that decrease control). And only take them down a few days later (so that the fort can get taken again by a complete bandit band).
ps. I am currently too lazy to give a list of all the things/actions that do or at least can reduce control (either uncapped or capped down to a certain value).