Once organ replacement technology catches up needs of humans nobody will care about tolemers. Do you care when a lightbulb goes out? Not if you have a box full of good light bulbs. The JWs metaphysically have solved the problems sciend is working on physically. When you have magic it is easy to give what is essentially a body transplant brain and all. One of the watchtowers latent fears is that science will make their new order a reality. They have been around about 120 years you can have full body replacements in the next 120 years.
Organ transplants have 3 major problems supply, rejection, and the inability to attach nerve endings to the new organs. Supply and rejection are both solved by genetic engineering and maybe the nerve ending problem too. The last hurdel is the brain. It is still a black box. So even with new organs human life will be finite. What the point of having an 18 year olds body and dementia.