I have been thinking about this very thing lately. Especially in the case of Mitsouko. I can understand the need for cheaper fragrances but it if we can view these great fragrances as works of art then cheapening them is equivalent to zeroxing a Picasso.
The first Mitsouko I had was EDT on sale so at least it was cheap but I barely enjoyed it. I decided to try a sample of pure parfum and there was no comparison. NOW I see what all the fuss is about. I imagine the original was even better and it is really annoying to know that the real thing was there and now it's lost.
As far as natural ingredients alone are concerned, I have two of Strange Invisble Perfumes scents; Eleuria and Trapeze. They are supposed to be all natural and they are very expensive but very strong, long lasting and unlike anything else out there. They all have a resinous accord which gives them their depth. At first they seem too much like tree sap or tar but the silage is fantastic and they have a haunting quality that seems to grip and mesmerize.