If you have some plants that are not at capacity, you can hire additional shifts to produce more, run on weekends, etc. Then you have additional labor costs, overtime, materials costs, etc. to recoup.
The manufacturing plant I once worked for had spare capacity for the better part of a decade, so it's not some completely unusual thing and was in fact part of our corporate strategy at the time to gain market share.
A new shift will take a while to train up and temps are... ugh... don't even get me started about the sort of people temp agencies send. We had some that only lasted a day for not listening and doing stupidly unsafe things. One of them nearly hit me upside the head with a piece of glass because he wasn't paying attention to where he was swinging it. That was his last day on the job, for precisely that reason.
So, raising the price on TP does nothing to increase supply in a 1 month time frame and reduces availability to the poorest. Instead, reduce demand with a bidet and limit customer purchases.