For some transsexual people, it can be hard to understand not wanting to transition. For them, being in the wrong body is torture and it's not possible for them to be content with the way they were born. But, that's not always the case, and here are some reasons someone might choose not to transition.
If you have any other reasons, or a personal story you'd like to add, please let me know.
Not all transgendered people find their body or social situation unbearable. If someone is comfortable enough as they are, they could have no reason to transition.
-Doesn't consider their body to be wrong
As hard as it may be to believe, there are trans people who consider their body to match their gender, even if that gender doesn't match the sex they were assigned at birth.
-Ability to Pass without
Occasionally, there are people who are able to easily pass as their gender without transitioning, or with only hormones. With the risks and costs of surgery, someone who passes easily may choose to only change their legal name, or not even do that.
Related: Some people choose not to transition to prove that you can pass as who you are without transitioning, such as for activism purposes.
-Inability to Pass
It's not possible to guarantee transitioning will allow anyone to pass as their true gender. The double-edged blade of increased awareness means that as more people know about transsexuals, the more critical they'll be of any "tells" and the harder it is to pass.
If a person believes they won't be able to pass post-transition, they can choose not to rather than take that risk, or to do the bare minimum to alleviate dysphoria while continuing to live as their assigned sex.
Not all surgeries are perfected, especially phalloplasty (construction of a penis). There's the risk of loss of sensation in both genital surgery and chest surgeries, they don't always look or feel realistic, and some people would feel just as bad with obviously fake parts as they do with the wrong ones. A trans man's view on phalloplasty (although this isn't the only view and many men are very happy with phalloplasty)
There are medical complications that make surgery life-threatening or prevent a surgeon from being willing to perform surgery. Some people can't even take hormones. For these people, transition is literally not an option.
-Wanting biological children
Usually, the final step of medical transition (and what most places that allow legal transition require) is a surgery that leaves the person sterile- or unable to have biological children. Estrogen & anti-androgens can also render trans women and those assigned male at birth sterile as well. Some trans women and other people who were assigned male at birth will bank sperm in case they choose to have kids later, but not everyone has the desire or money to do this. For people who transition with hormones pre-puberty, this also isn't an option.
There are other reasons a trans person may not want to transition. For example, Lucas Silveira will not take testosterone for fear of what it may do to his singing voice. There are just as many reasons people may not want to transition as reasons that they may want to.
(Trigger Warning: The links involve transphobia and mistreatment of LGBT people)
There are still countries and states where being openly LGBT is a giant risk. The law doesn't always protect trans people, or even discriminates against them. Not everyone can move to a more tolerant place, and in places where it's illegal to be gay, it can be impossible to find support much less have a chance at transitioning.
Some people who transition do so at the cost of their family. They can be disowned by parents, cut off from extended family, left by a spouse, and even lose contact with their children. Although there are cases of everyone being fully accepting- that doesn't always happen and people don't always "come around" to accept it. Having to choose between your loved ones and transitioning is not an easy decision for anyone, and often it's only people who have a strong need to transition that will choose the latter.
In the UK, Canada, and possibly a few other countries, transition is covered by health care. In the US and other countries, it's all out of pocket. Some insurances will cover hormones, therapist costs, and hysterectomy/orchiectomy, but most surgeries are listed as "cosmetic" and not covered. Each surgery costs thousands of dollars, not including the cost of any travel, hotel bills, etc. Many transgendered people are estranged from their families and loved ones, and have no one to care for them after the surgery, which means they have to pay someone to do that as well.
Because gender identity isn't protected against discrimination everywhere, transition can include losing a job and being unable to find a new one or having to completely relocate to a place that does protect it. All of which make it hard to afford surgery.
Many religions don't support transition and see transgender people as sinful. Or, like with homosexuality, feel it's a choice and transgender people should just choose to be normal. For people who are very religious, the risk of going to hell can outweigh the desire to transition. Some transgender people are able to reconcile their religious beliefs with transitioning, but that's not true of everyone.