Flowers are part of the natural world, and people have been using flowers forever to make their houses smell nice, their weddings look pretty, and to express their love. But, at least according to "One Perfect Rose," that was then, and this is now (as in 1926, when the poem was written). Nature just isn't cutting it anymore. Sure, roses are great and all, but in the modern world there are limousines and other modern items that are really a whole lot better.
Live in the now, folks. Nature is the past; technology is the future. Shiny new advances in technology have made nature a lot less interesting than it used to be.
Roses rule! Technology may be cool, but nature will always be purer. Always. Forever.