dv_dt and existencebox hit it well - cultural more than technical. But, the cultural changes impacted policy. I've posted the following article in the past, but it provides a clear image of the issue - from one of the people who set the wheels in motion.
>But there is a theme that threads through and ties together all the strands: many of the most talented, driven Americans used what makes America great–the First Amendment, due process, financial and legal ingenuity, free markets and free trade, meritocracy, even democracy itself–to chase the American Dream. And they won it, for themselves. Then, in a way unprecedented in history, they were able to consolidate their winnings, outsmart and co-opt the forces that might have reined them in, and pull up the ladder so more could not share in their success or challenge their primacy.
>By continuing to get better at what they do, by knocking away the guardrails limiting their winnings, aggressively engineering changes in the political landscape, and by dint of the often unanticipated consequences of their innovations, they created a nation of moats that protected them from accountability and from the damage their triumphs caused in the larger community. Most of the time, our elected and appointed representatives were no match for these overachievers. As a result of their savvy, their drive and their resources (and a certain degree of privilege, as these strivers may have come from humble circumstances but are mostly white men), America all but abandoned its most ambitious and proudest ideal: the never perfect, always debated and perpetually sought after balance between the energizing inequality of achievement in a competitive economy and the community-binding equality promised by democracy. In a battle that began a half-century ago, the achievers won.
http://time.com/5280446/baby-boomer-generation-america-steve...