There's something irresistible about spandex. Part of the appeal has to rest with the fact that nylon-spandex fabric is just so comfortable, shiny and stretchy.
Spandex fabric composition: 80 % Polyamide (nylon), 20 % Elastane (lycra)
Spandex is almost like a shape-shifting fabric. It can adhere to anyone's frame. This shiny fabric has been popular enough to create a craze over and over again, which has happened for a reason.
The popularity of spandex clothing in the mainstream culture has waxed and waned over the years just like everything else. In the 1980s, for instance, it seemed as if almost everyone was wearing spandex, especially the variety that came in neon shiny colors (pink, blue, green and black). Lots of women looked like dancers at the time, whether they were any good at dancing or not. Part of the comfort factor involved with spandex is a simple fact that the material doesn't restrict one's movements. There's a reason why dancers go to the dance floor, gym and elsewhere wearing their shiny clothing.
Another part of the comfort factor with is the fact that it is just smooth to the touch. A women's legs feel effortlessly soft and silky when they're wrapped in shiny spandex, which is an inherently sensual type of material. A woman who wore an entire suit (catsuit) made of this material is going to look like she is wearing an additional layer of skin, except this skin is smooth, clear, glossy and perfect.
Bodysuits and catsuits have been popular motifs in science fiction for a long time. Perhaps people look at these comfortable suits and imagine an ideal future in which the most important part of all clothing is comfort and sensuality. In this future, women will be free of some of their physical insecurities. They will be more expressive and free to be themselves. Nylon spandex may truly be the fabric of the future on many different levels, but you can enjoy it just as surely today.