Here's how they pulled it off.
They deliberately started propagandizing women to get into the work force, to be "independent" of their wicked husbands, to have "careers" that would "fulfill" them (as if pushing papers in an office was more fulfilling than raising children), etc. etc.
As more women got into the workforce, it started to drive wages down, since there were fewer jobs for men, who now had to compete with women for many of the same jobs.
Then, as more families were two-income and had more money coming in, prices started going up because more people could afford things at higher prices.
With this vicious cycle you eventually got to a point that it was extremely difficult if not impossible to raise a family on a single income unless it was a high-end type of income.
Back in the day, someone like my neighbor who worked at an aluminum plant, or as a machinist, or in a factory, could own a home, a couple cars, could raise quite a few children ... all on an income that these days could barely get you a one-bedroom apartment, a car, food, insurance, etc. for a single guy. People could even get by fine with a living wage just working at a gas station or grocery store, if they didn't have a family. Now, with those types of jobs you simply can't afford an apartment and car (not even close).
Now, in those days, most companies also had solid pension plans, and many people worked their entire careers at a single company, and then collected large pensions at 55 (having worked a little over 30 years there) and retired.
At some point, however, they created these "401(k)" plans, which made it so companies could dump their own pension plans, but that was partly a scam so that companies wouldn't have to fund pensions and also to prop the stock market. Few people invested in stocks back then, as interest rates on bank CDs were very reasonable. I recall my father locking down a large sum of money at 12% CD rates for a long time. That's another reason they dropped interest rates at banks, where it was next to worthless to keep your money in a bank, even with CDs, when they were paying out a lousy 2%-3%. So desperate people also went into the stock market, and that's the only reason the stock market has been inflated all these years, by forced participation via 401K.
Then the 401K contributions / matches from employers got increasingly stingy, pensions went away completely, and companies had no problem laying people off even if it could save them 1% on their bottom line. So the idea of a person working 30+ years at one company became completely non-exsitent. Since employers had no loyalty to their employees, that attitude was reciprocated by the employees ... so if they could jump companies to get a 10% raise (which they could never get within their company), off they went. That also helped wipe out the company-based pension system. I knew some people in my father's generation who told me that they worked 55+ years at various companies (some union others even non-union), where there were quite a few "slow" years for the company, but the company kept them on, and they sat around playing cards all day during the slow periods. Companies realized it would be more expensive to hire new people and retrain them than to absorb down times, plus realized it would hurt morale, cause people they had invested in by training to leave, etc. At some point they stopped caring about these intangibles and only cared about next quarter's profit margin ... short-term thinking, not long term.
Then of course you had the offshoring, the illegal immigrants, etc. ... all compounding the effect, with the goal being to wipe out an independent middle class, and ultimately make us all dependent entirely on the government.