In Populuxe, Thomas Hine suggests that the emphasis on disposability and portability and convenience was designed to call into being to a new "flexible personality" coming into being -- this would be the kind of person who would cheerfully adopt a new wardrobe, if fashion suggested it was necessary, or a new city if moved by his bosses at whatever transnational company he worked for. These goods, the push-button, portable, streamlined goods of the era provided material basis for this new personality, the personality didn't precede it -- a classic case of ideology functioning as a material, concrete thing, embodying an approach to life that is not organic but comes to seem that way by sheer ubiquity, by a conspiracy of related institutions: the government, industry, art, advertising, R & D firms, etc.
The climate of instability created by a world where trends were constantly changing, and jobs were becoming ever more insecure, was thus given a positive spin by this new material culture, which implied that such transience and the decimation of established, comforting traditions was actually an openness to spontaneity, which was everywhere billed as more authentic, more real, more self-fulfilling. In this way the disorienting sense that "all is solid melts into air" -- Marx's classic description of life under capitalism -- is turned into something to celebrate -- the wonderful joy of everything novel. Novelty becomes an end to celebrate in and of itself, to provide an alibi for capitalism's relentlessly churning economic engine and the upheaval it inevitably wreaks.
The cult of spontaneity has its roots in 18th century fascination with "sensibility," or the ability to cry spontaneously at others' misfortune, thereby proving the soundness of your feeling heart. This was immediatly capitalied upon to sell goods, as a spontaneous reaction is an unreflecive one, and an unreflective response, an impulse, is easy to manipulate into impulsive consumption. Sensibility also encouraged a kind of individualism, since your concern typically stopped at the expression of your own feelings and didn't concern itself with social root causes. Sensibility, in some ways, has been replaced in America by evangelical Christianity, with its emphasis on instant conversions, the truth of the heart (as well as the Bible) and that sort of thing. That evangelicals are uninterested in root causes is evident in their voting patterns, which shows that they are not especially concerned with causes for moral turpitude (poverty) and are more interested in punishing it at the expense of their own chances for greater economic security.
All the innovations of the 50s -- disposibility, portabililty, convenience, stylishness -- all assailed the basis of utility for purchasing things. It was no longer even required of people to think to themselves that usefulness was a criteria. And in the absence of uniform religious tradition, the basis of utility may have been what anchored the national tradition, an understanding that a Benthamite rationality undergirded our collective morality. That is gone, lost to fashion cycles. Perhaps it's the loss of that, and not of some other religious tradition that has led to evangelicalism growing so much.