No no! Higgypop that is a very very good question! The reason why such an elaborate system is being used is because the brain never sleeps. The unconscious brain is always active. Working. Seeing. Hearing. It never shuts down except after a substantial period after death. The A.I. knows this and that shutting down the brain will kill the body. Useless to the technology.
The best question to ask is that why couldn't the A.I. correct the atmospheric environment that cut off the sun which is what the humans did during the conflict with the A.I.? Why couldn't it restore the atmosphere to what it was being that it initially ran off solar energy to a great degree?