And, in the meantime we continue to deny an entire set of people rights they should have and bury our head in the sand to the current real world problems this poses.
Even if you hold the position you stated and wanted that change, we can't deny someone rights in the current system for some future better situation. There is an immediate and real world problem that needs to be addressed while you strive to implement your preferred system.
Except that when you put your energy into lobbying instead of going your own way and DIY, you're supporting the machine known as government and legitimizing its role as arbiter-of-all-that-is-good. When your campaign succeeds, it does so at the expense of pigeonholing the entire issue of unnecessary marriage regulation into the simplistic "gay marriage", and people consider the entire issue solved and look for the next thing to feel progressive about. But even worse, your narrow success then serves as an advertisement of the system working and covers up the fact that you're actually three steps back due to increased government intervention everywhere else.
Yeah, the "DIY" approach: ask all the gay couples out there who tried that with big expensive packages of legal documents that ended up being worth sweet fuck all precisely at the moment they needed it.
Part of the reason there is a push for gay marriage is because the alternatives (civil partnerships, "DIY" marriages using contracts) and they've failed to provide the necessary protections for couples in the way marriage rights seem to.
There is a compelling societal need to be able to say "here are people who are in an intimate, long-term trusting relationship for the purposes of decision making, finance, tax and so on".
I wish you luck in your campaign to find a compelling and convincing political and intellectual argument for something that would serve the social goods that marriage does and would effectively replace marriage for gay and straight couples. Until then, I'd quite like to be able to get married to someone of the gender I'm actually attracted to. (And as of Saturday, I will be able to, thanks to the marriage laws in England changing.)
The basis and functioning of the UK government seems quite different than that of the US. For better and for worse, a large part of the American foundation is the ability to abstain from involvement with government and go your own way. Treating USG as if it's an authoritative entity that has an ultimate say over any aspect of one's life erodes this ability, and we get left with the worst of both worlds - a broken system that we can't avoid (eg what happened with healthcare).
And yeah, making this argument widely compelling is going to take a lot more than luck. Immediate short-term realities tend to dominate over long-term abstract ideals.
Even if you hold the position you stated and wanted that change, we can't deny someone rights in the current system for some future better situation. There is an immediate and real world problem that needs to be addressed while you strive to implement your preferred system.