In some circles, the mere suggestion that this should be a policy goal is insulting, as it hints that single-parent homes are inferior. Our government isn't really allowed to prefer one over the other, even if it would result in less misery.
Furthermore, the tools that government has at its disposal to encourage two-parent households are few and clumsy. No decision to stay together has ever hinged on a slightly higher tax exemption, or some other priority access to the bureaucracy.
The writer's room of some Hollywood sitcom has more power than Congress in these matters. I doubt very much that they are interested in giving up on the show that makes jokes that discourage such, but even if they did, that's one show when the real culprit is the entire weight of the entertainment industry.
We might as well talk about how it should be a policy goal to raise the speed of light to 750,000 miles per second.