Good thought. I explore some of this in post on my blog about what makes the scent of a flower.
In my mind there are four key reasons why you can't just replicate a flower fragrance from a headspace analysis:
1) each type of capture mechanism yields different results, plus time of day, age of flower etc all influence what you capture - so you have also to make a judgement about what you want to attempt to match
2) there may be stability considerations: not everything in a flower scent is stable in a liquid perfume
3) there are likely to be both safety and regulatory reasons why you can't replicate it anyway: not everything that is safe to smell is safe to put on your skin and even if it's safe you may not be compliant with regulations.
4) flowers generally manufacture more scent on a constant basis, so the scent may be all or nearly all middle and top notes - to make it work in a liquid fragrance you're going to need fixatives and base notes.