Human needs fall into 4 major categories: temporal, spiritual, emotional, and social. The traditional family is the most efficent vehicle for meeting these needs. There isn't a social organization that can outperform the family in terms of effectiveness, or efficency with regard to taking care of people. Unfortunately, the family us under seige and people are suffering the effects of unmet need: drug addiction, overeating, promescuity, consumer debt. The destruction of the traditional family is the #1 contributer to poverty and crime in this country.
When it comes to traditional men and women's roles the LDS church teaches that families do better when fathers (generally speaking) focus on their family's temporal and spiritual needs while the mother focus on the emotional and social needs. When I say better, I mean the family as a whole does better. If our roles were reversed, my wife could likely earn more money and establish a more spiritual family environment than I do. But she can't outperform what both of us can do together with me focusing on some needs and her focusing on others. Fortunately, the most skilled parent (my wife) is assigned to the more critical task of nurturing the children.
I have a friend who studied to become a CPA and wanted a simple 9-5 job so he could stay home more with his family and do more of the fun social and emotional stuff. Well, turned out that as a CPA he could only get a job that earned 24-36,000 a year and the financial stress almost tore his marriage and family appart. Finally, he recognized that an extra sacrifice needed to made and that it was his primary role to "bring home the bacon." So, instead of asking his wife to get a job, he started working longer hours, traveling, and getting more training. Now, he brings home $80,000 and his marriage and family is doing great. He still spends plenty of time with his wife and kids. But when an extra sacrifice needed to be made, he knew he was the one who needed to make it.
Did the kids miss their Dad? Sure. But, all that time they had a stay-at-home mom who was their to do care for their social and emotional needs. Consequently, they are all very intelligent, motivated, straight-A, straight-arrow kids (and they have had serious issues they've needed to work through). If mom had decided to work instead of Dad working harder, things likely wouldn't have worked out as well. Having 2 people doing the same job is too inefficient. Division of labor is the most efficent way to get things done.
Sociologist have loads of evidence to support my argument. If mom wanted to work also, consider how much it cost to pay for her wardrob, transportation, and childcare expenses.
Salary.com determined that a stay-at-home mother might be paid as much as $134,121 for her contributions as a housekeeper, cook, day care center teacher, janitor and CEO, among other functions. So, unless mom is bringing home that kind of cash, she is more valuable at home. But then that still leaves the kids without emotional support for which you would have to factor the cost of the drug rehab or other counciling everyone will need because noone was there for them emotionally when they needed it.
The reason why God makes generalized commandments is because he is looking out for the good of the many. Most rules work this way. Generally speaking, families do better if the most skilled parent is home doing the nurturing (usually the mother). There are exceptions to this. But, God makes rules like this because he understands that majority of people will have successful families if they stick to the rule. And even if you were the exception, God would still likely expect you to obey the rule because the rules are easier to keep if they become generally socially acceptable and traditional. But there are always exceptions and if both parents must work or the wife works and the husband stays at home, it's not the ideal, but then you do the best you can.