Yes, gay ideals have shifted since the 70s, but the shift has been more gradual than you seem to be saying. The shift may have started in the mid-70s with the implosion of the Gay Liberation Front, but it really wasn't complete until less than ten years ago. The 30-year mark you suggest would mark the beginning of the AIDS crisis. At that point, Larry Kramer gained a prominence in the gay community that he had not previously held, but Kramer was always a conservative. See his book Faggots for example. Despite his involvement at the beginning of ACT-UP, he was still ideologically out of step with the majority of the high-profile gay activists. He was, for example, calling for the closing of the bathhouses when most gay activists viewed this as a repressive measure of the anti-sex crowd.
AIDS was the catalyst for breaking the closet doors for many gay men. It also created an ideal that hadn't previously been articulated, i.e. "chosen" families--groups of friends who functioned as quasi-families in lieu of the families who had thrown them out.
Even the Hawaii and Alaska marriage cases in the mid-90s were viewed by many in the gay community as a distraction from more fundamental issues like basic civil rights legislation--employment, housing, and public accommodations. Funding for AIDS education and prevention was also taking up a lot of energy. If gay life was becoming normalized, it was because of the "great shower debate" (precipitated by Bill Clinton and presided over by Sam Nunn), Will and Grace, and Ellen Degeneres. Even in 2000 we were still embroiled in a philosophical debate about whether we wanted a state-sponsored marriage, whether civil unions were adequate, or whether the state should get out of the marriage business altogether.
I would date the shift from the mid-90s because almost no one (except Larry Kramer) was even talking about mimicking the pattern of heterosexual marriage until then. And all this was was merely a shift in a social model that added a couple of points onto the gay political agenda that was already in place.
None of this has anything to do with national economic policy. At most it would affect individual tax status and entitlements. Thus, I see no serious connection between the gay agenda and the agenda driving the Republican Party (tax cuts and religious oppression).