First, I think you're confusing the term "transgender" with "transsexual". As others have stated, transgender is an umbrella term for anyone that crosses the gender divide.
To answer your question, I'd look at available statistics. How many TGs go on to live full time (or near FT), or take hormones, or wish to transition? Few, in comparison to the TG community as a whole. And this doesn't make those who've achieved inner gender balance, fetichists.