There is no luster or appeal of marriage anymore in this modern economy.
It used to be that a man and a woman would get married and their unique attributes, defined by their respective gender roles, would form an adequate union. The man would provide for the family through labor, while the woman would be responsible for the duties of the household (raising the child, which is by no means less important).
But, in this day and age marriage has practically no significant meaning; kids are raised largely by a series of institutions, be it pre-school, middle school, or otherwise. Fathers and mothers often have little time to devote to raising their children, and in this day and age a man's single wage is often not enough to make ends meet.
The only thing I'm aware of that marriage accomplishes is some sort of superficial role where the routine fucking, sleeping, and eating together, etc. is given some higher meaning than it actually has.
There's that, and there's also tax breaks. Plus some people actually do set it up the classic way, with the dad working and the mom nurturing. Ends can easily be met with less than the median wage, it's just that a lot of people take certain luxuries for granted and think they are required.
The notion that throughout history the man worked all by himself outside of the home is far from the truth. In the stone age, men probably did most of the hunting because they were more expendable than women, relatively speaking. In the agricultural era, women worked the fields. In the industrial era, women (and the kids too!) worked the machines.
The time that you're remembering is entirely fictional. Only the upper and middle (not working) classes in a select few industrialized nations lived this lifestyle and only briefly. What you were seeing was the result of the post-war economic boom that had shifted much of the wealth in the world briefly to the United States and its allies. As the rest of the world came back online (industrially), competition increased, wealth was redistributed, the playing field leveled again, and women had to work again.
Even while all this was going on, do you think women weren't working in the Soviet Union and China? Even in the wealthiest countries, working class women still worked outside the home regularly, it just wasn't glamorous, so it wasn't seen on television. So basically, what I'm saying is that 1950s television was fiction. Get over it.
Mostly tax benefits. Sample of UK tax law:
"Capital Gains Tax
All individuals have an annual capital gains tax exemption of, currently, £8,800 (2006/2007 tax year).
However, for a married couple that is potentially doubled to £17,600.
The reason for this is that you can transfer assets which are subject to Capital Gains Tax between spouses completely tax free.
Thus, if you know that you are going to sell shares in the tax year which will generate a gain of £15,000, you could transfer to your spouse the shares which were likely to tip the gain over and above £8,800.
The same would be the case with a second property. You can make sure that you and your spouse shared the gain to take advantage of both annual exemptions."
If you have taxable assets and can get a pre-nup, it's well worth getting married, since tax is usually the biggest weight on your investments.