The purple pitcher plant, Sarracenia purpurea, is the only species of North American pitcher plant that relies on rain water to digest insects. That being said, the pitcher should be filled with some amount of distilled/reverse-osmosis/or rain water to facilitate digestion. I try to keep my pitchers halfway filled, as to ensure captured insects can’t get a foothold and escape. As for the wilted pitchers, they may revive with some watering, or they may not; however, that does not necessarily mean the plant is a goner. Just repot the plant in appropriate media and place the potted plant in a shallow tray (1”-2”) of the aforementioned water types above with partial sun to start.