No-one has ‘gone all the way’ or anything even remotely close.
Individuals who have altered their secondary sexual characteristics through hormone treatment and surgery have, at very best, altered their appearance to imitate more successfully a member of the opposite sex. Nothing has been ‘reassigned’ it’s just been altered, removed or added - there is no surgery going that can turn a functional bit of male anatomy into a functional bit of female anatomy,
Biological sex, however, is dictated at a cellular level by chromosomes expressed in every single one of the millions upon millions of the cells in the human body. A man has male lungs, male heart, male liver, male bones, male skin - male every single organ including a male brain. And the same for women.
the fact that changing only those parts of the body relating to physical appearance and sexual function is regarded as a proxy for an entire change of sex tells us a lot about the motivation for the change. There needs to still be actual women, (distinct from TIM) for men to have something to want to look like ( I don’t see anyone campaigning for MtF lung transplants or kidney transplants to be more ‘female’ - it only seems to be the bits that alter appearance which matter, which is odd if the driver is an innate feeling of being female?) it’s almost like the innate feeling is of wanting to look female rather than be female…
(And about the inability of many humans to hold in their mind the two distinct meanings of the word sex - sex as what we are, and sex as what we do.)