AOG: "How can you possibly equate a terminal illness situation with a none life threatening situation, such as gender re-assignment? "
The problem with this point is that, again, it seems to belittle anything that could be seen as a mental health issue -- and, in their way, they certainly are life-threatening. Not physically, but anyone who is driven towards depression and doesn't receive the attention needed can be at risk of death just as much as someone who, say, has suffered a horrific physical injury. It may be less visible but it is no less valid.
As to the rest of your post, I suspect that if there has been such an increase in referrals then it's to be expected as a result of the progress that has been made so far -- in being more accepting of transgender people, and on the whole less judgemental. There remains some way to go, but if people feel under less pressure to hide their transgenderism then it's not surprising to see a corresponding increase in referrals at clinics.
Pixie, re the desert island question: dunno. Very possibly not, I suppose, because arguably the entire point about trans* issues is that gender, as opposed to biological sex, is very much a social construct. Absent such contact with society I can well imagine therefore that it might never be an issue. But transpeople aren't stuck on desert islands and they do grow up in society and so it does become a problem. In the future, perhaps the traditional understanding of gender will change so drastically that it again stops being an issue, because people can just be themselves free from prejudice or judgement. We can but dream.