It already
has been for a few years on the design level. Since 2015 for certain a lot of scents have been assisted where the nose creates a formula and its fed into a machine learner which cross references what was popular, similar etc.. and they tweak it accordingly before focusing testing. A pure AI only scent hasn't been made yet, as far as I know but they have been working on it behind the scenes:
Can artificial intelligence create perfume even without a sense of smell? Turns out it can examine the various substances that make up perfume and analyze it against databases of sales and demographic reports to create new combinations working alongside master perfumers.
www.forbes.com
Why? Greater profit margins because then they own every single piece of the puzzle and could do what they want due to the aforementioned rationing of components so no one else could create smells like them.
Some folks I know are equally hard at work making their own captives but it requires a vast knowledge of chemistry and a decent lab so there will always be an underground in that sense because some dudes just won't quit.