Because, you know, they've performed the operation on over 1000 mice, none of which could they keep alive for more than a day.
Of course, it would be in China, where they're cavalier about carving up human beings for organ transplants (very Tleilaxu home world - need to find that novel) and don't tell lies about human fetal tissue (billboard says "heartbeat at 18 days - uh-huh, a mass of a few hundred cells contracts rhythmically to do what, exactly, for a mass of a few thousand cells? Bit liar-like to call that a "heartbeat.").
Even if we're being generous with the definitions, I'm barely an amateur biologist, and I know a "head transplant" is pure science fantasy, and will be for the better part of my life.
You've got breathing, you've got blood flow, you've got muscle tissue, and nerves to control muscles, and a spinal column to control autonomic functions like heartbeat and breathing and digestion and endocrinology, etc., etc.
Plus, the term is wrong "head transplant." Normally, we use the term like "heart transplant," or "kidney transplant" to mean "putting a healthy organ into a diseased body."
In this case, it's a BODY-transplant - putting a new body under a healthy head.
2017, my tight butt. 2 1 0 7, maybe.