Widespread acceptance of homosexuality signals an end for a distinctive gay culture. This is because gay people are already in the mainstream now in the United States. Their status as a minority or a subset of culture is gone. Political correctness has deemed that they are in the majority with heterosexuals now.
African-American culture is distinctive from other american culture even though there is a widespread acceptance of African-American people in the USA. In fact, widespread acceptance of homosexuality may even lead to a stronger and more visible gay culture as people are more likely to be open about what their culture if it is more accepted.
Increasing acceptance of homosexuality does not seem to be leading to a lack of a distinctive gay culture, and if anything is going to be the case, the ending will lead to an even more distinct culture, just as feminism and the civil rights movement did in their respective cases.
No, this will not end the gay culture, because just because people are more accepting of gay people, does not mean that they are going to change their ways and start practicing different things that the gays do. There will always be that separation that we have today with gays.
It's hard to believe that a distinctive gay culture will ever end. And the reason for this is because the homosexual population, relative to the rest of the world, is very small. And whenever you have a minority who shares the same quality, a distinctive culture emerges from it whether it's accepted or not.
I do not believe the widespread acceptance of homosexuality signals an end for a distinctive gay culture. I believe that is entirely left up to the people who are part of that culture and rather or not they want to maintain it. It will depend only on their choices and not others.