Do Designers influence Street Style or does street style influence Designers

I have a theory about fashion. Some believe that designers are influenced by what is seen on the street and others believe that normal fashionistas are influenced by designers. Complicated, right? Well I believe both. In the end, trends have been started and created mostly be people who did not mean to be stylish, Most things done in fashion today or that will be done in the future has already been done before and designers are updating the trend for a more modern take on the trend. In my opinion anything new in terms of fashion started the day of our existence and ended in 2000. We have gone through tons of styles. You can pick up something from a vintage thrift store and look like you are on trend at the moment. So why do people pay such a pretty penny on high end designers? It's because of media, vanity, and a bit of insecurity. We pay so much on a lovely Louis Vuitton bag to prove the amount of money in the bank more than actually liking the bag. Anyways that's another topic lol. So anyways, all the roots of fashion have been established, the fashionistas, celebs, and hipsters wear these trends old or new in their own way and a collection is designed around this person's style. This collection becomes popular and is similar to what is going on with other collections and the main styles of these collection become the trend of the season and this influences those who started the trend to begin with, the fashionistas, the celebs, and the hipsters. An example of this can be seen with fall 2009. Marc Jacobs and many other designers were influenced by 80s fashioned and designed their collection built upon this era. Madonna was a main fashion icon of this era and she was in mind for designing these collections along with other singers, movies, trends, etc. The collections are released and 80s becomes the in trend thing. Madonna wears from these collections realizing or not realizing that she is wearing fashion inspired but what she and friends and celebs of her time have already done and in fact a similar dress or accessory could be in her closet from her like a virgin days. This is what is happening a lot and what will continue to happen. So what do we do realizing such a thing? We shop. We still buy the beautiful but overpriced designer brands. We don't mind some cheaper vintage peices though. We mix and match the old with the new and we become the inspiration. We then buy from the new collection inspired by us and the cycle goes on and on. Of course there are some new ideas and and totally new creations and we will buy them and wear them differently and that totally unique and avant garde piece worn differently will be remade with a different aesthetic in the future.