Short answer: Never. Not even in 1,000 years.
Long answer: Think about the other marginalized social groups in the last 100 years. Women didn't even have the right to vote 100 years ago. The Civil Rights movement in the USA was only about 50 years ago. Gays and lesbians after that. And now the fight for transgender (but really, transsexual) rights.
The common thread between all these movements was/is visibility. People who were a part of these marginalized groups put themselves out in the public eye. They laid bare their real names, real reputations, careers, and families to fight for acceptance and legal rights. I'm sorry, but I don't see crossdressers ever doing that. So many CDs can't even leave their house!And even for the ones who do go out - are they willing to risk everything, as women, blacks, gays, lesbians, and transsexuals have done? Are CDs willing to proudly and publicly declare their existence, baring their entire lives to the public, as individuals in other marginalized groups have done? How many women, blacks, gays, lesbians, and transsexuals sacrificed blood in order to fight for their rights? How many of them were willing to sacrifice their very lives?
Now ask yourself, how many CDs would be willing to do the same thing? And that's why CDs will always be relegated to the fringes of society. For another 1,000 years or more... which is sad. But that's what I see.