The difference we have here is that I don't think it's anti-discrimination laws that change society. It's communication and confrontation of evil that changes society, and that happens over time.
Anti-discrimination laws didn't pop out of nowhere; the idea had been building over time, and when they hit the courts, new laws where made, instead of addressing the issues with the laws that were already made.
You argue that the status quo remains unless something is done - I agree, however that something is not law. There's a word for forcing morality on people: bigotry.
Allowing black people to use public roads is a matter of upholding existing law: All people are created equal. It took a lot of time, but eventually America began to understand the inconsistency of that law - A law that wasn't forced on people, but rather one that people chose to support when they supported the revolution. Change didn't happen by law. The change happened by people no longer standing for it.
The fact is, whether the group of people is gay, black, or whatever, there will always be a people group that is being discriminated against by someone. 20 years from now, we'll be coming up with more laws about group x, and pundits will say, "This is just like the gay rights wars of the early 21st century - we need more laws!", just as much as gay rights pundits are making comparisons to mid-20th century race relations, and demanding more laws to address an issue that people are already changing.
The point is this: laws don't change people. You can't enforce morality on people. Enforcement only creates bitterness and more problems. Change happens because of cultural influence, and that cultural influence is the input to the change function, not the output of f(law).
Your last point is that state-recognized marriages get tax benefits, but that's an issue with the tax code, not marriage. Attempting to fix the problem by defining/redefining marriage is like spraying air freshener without flushing the toilet. The problem is the tax code, not marriage. If you remove the concept of a marriage license, there are no tax benefits, for anyone, no matter their sexuality. The state simply has no jurisdiction over marriage. It's an inherently personal matter. Subsequently, Ron Paul's removal of the IRS also addresses the larger problem.
This is why I keep touting "freedom freedom freedom", because that's the core principle from which the solution is grown. Get the government out of the way, so that people, together, can work out problems. Enforcing morality by law encourages segregation. Staying out of it, thereby forcing people to deal with themselves and others without running to mommy government...that's the long term solution.
Freedom solves all problems. It's arguably the ether of human relationships.