This is quite possibly the worst analogy I've ever seen. It would be better as an analogy for statism. Cuz, ya know, you don't really own your house. You're just leasing it from the government, and it can be taken back for failure to pay rent or for the 'public' good. That's the meaning of the term "real estate."
I saw a sign in a picture that said "Gay marriage is a civil right." No, you see, it's not. A civil right is a right that is granted by the government. Gay marriage is not granted by the government; ergo it's not a civil right.
(The triumph of logic will take another millenium because of things like this. People accept unproven statements of fancy and it falls to the people with actual knowledge to disprove an infinite number of fallacies, which is itself a thankless task that never ends. Just... don't believe things without some sort of rationale.)
Anyway, one could reasonably argue that gay marriage is a natural right, depending on various things, but not a civil right.
What is civil marriage? It is a government license that comes with various restrictions and privileges. It has several purposes:
1) It serves the economic purpose of the marriage contract without requiring a tribal society, fickle common law, or actual written prenups. God Forbid you actually scan over a legal document and sign it. Common Law marriage prevents people from escaping government regulation by default.
2) It allows feminists or other interest groups to exert social pressure, since people's marriages are now controlled by the majority opinion, rather than an understanding between husband and wife.
Arguably the system now is better than the traditional system, but it's inferior to a system where couples sign prenups and have the priest sprinkle water on them.
So, essentially, gays want these positive privileges and benefits and restrictions. I don't have a problem specifically with gay marriage, since God can strike them down if He sees fit. In fact, legalizing gay marriage would let the GOP pick up a whole .5% of the voters who are gay, but not thieves or liars.
Those voters might become disillusioned and vote for Ron Paul or something, but it's a chance we have to take.
The better solution would be the end of civil marriage, which has evolved somewhat over time. Of course, no one can comprehend that. But how will we get married if the State of California doesn't allow it??? Well, the State of California didn't exist in 1000 BC, but people still got married. I'm sure you can figure out how to
2) Ovulate, Copulate, and Overpopulate
3) Sign a contract that prevents one spouse from running off and leaving the children etc.
The last one's not a problem specifically for gay couples. (Adoption is an issue for heteros as well so STFU with your objection.)
Well, I've already belabored all the consequences and side effects of ending marriage licensing, so I'll stop here. The takeaway is: Don't make up nonsensical analogies.