This is a difficult topic, and as such I will lead in with a bit of a disclaimer: I make absolutely zero judgments against those who commit suicide. Being driven to suicide almost by definition means you are in a state of mind which foregoes all judgment.
However, I believe unequivocally, suicide is never, never, the answer in these sorts of scenarios (ie: not talking about someone who is terminally ill at the age of 95 and just suffering, entirely different discussion). Because when it comes down to it, the "it get's better" mantras are true. Does that mean her life would have been easy? Of course not. She faced an uphill battle in escaping family, getting an education, getting a job, affording needed medical procedures, and just being able to be herself. But... well... which of us doesn't? (Many of those issues aren't even trans specific by any means.) I don't need to go into the countless stories on this forum of depression, discrimination, poverty, sexual abuse, or pretty much anything else under the sun. And yet, people survived and went on to become happy(or at least as happy as the general populace which is really all anyone can ask for).
And honestly, while Leelah's issues listed in the original post are certainly horrible, they are also unfortunately extraordinarily common for trans youth. They absolutely could have been overcome in time. Would it have been easy? No, definitely not. But life isn't easy, never has been. Would it have been a guarantee? Nope, definitely not that either, but then that's just not how the world works, nothing is guaranteed. But then that's a good thing, because it also means it's not a guarantee it will be hopeless. I've seen quite a few stories of people escaping those sorts of situations and lucking into money, or finding love, or any of a number of things. (The "rich boyfriend paid for SRS" narrative seems oddly not that rare for example.)
(My experience with suicide: When my parents divorced when I was 16, after her marriage of 35 years that she had put everything into ended, my mother attempted to commit suicide a number of times. She saw no hope for the future, and she believed she was a burden on everyone else around her. Essentially, if my dad didn't want her, then it stood to reason no one else did too. Of course, this was far from the case, and the suicide attempts had far more dramatic impact on me and my younger brother than the divorce itself did. Over the following years, she tried a few more times, some in secret which she told me about much later (when they failed she wouldn't seek medical attention for it, ultimately damaging her liver pretty badly, her life only saved because she was very overweight at the time and she was taking dosages that would have been fatal for a smaller person). Ultimately... things got better. She was never happy about the divorce, and never dated again or anything like that, but she lived to see her grand children be born and grow and also was there when I needed her desperately during my own issues in my 20s. When she passed away from cancer in 2014, even if life was not what she thought it would be or what she may have wished for it to be, she was ultimately happy and did not want to die.)