There was a magical cure for this back in the day. In ancient times pumpkins like these were displayed outside where the weather was cold enough for them to keep for weeks. Now that we’ve raised the planet’s temperature, that isn’t a good option in many places.

There actually is. You can either spray the inside and cut surfaces with hairspray, or smear them with Vaseline. That will seal it from the atmosphere and it should last a lot longer.