I highly doubt toilet paper manufacturers will add production capacity. In the long term, toilet paper consumption must be absurdly stable. If people are buying extra toilet paper today, they'll buy less toilet paper in the future (unless they start having toilet paper bonfires or something).
They won't if they can't sell it for higher price. But adding capacity could just mean running extra shifts or producing on the weekend. But that means higher costs (paying people to work on the weekend).
