Some of the octopus are still alive today.

For anyone looking for a serious answer, the 1977 experiment seems to have extended life for several months (which is almost double the lifespan in some species), before they died for another reason which was not explained.

What I gather is that the optic gland controls all hormone secretion, and although they were able to prevent the digestive system from being blocked by removing it, the same gland likely is necessary in other areas.