^ Safrole and most other "specialty" chemicals used to make MDMA are closely monitored in Australia under the
Chemical Diversion Code of Practice and as safrole is listed as a carcinogen, I doubt you'd find it in many massage clinics or aromatherapy shops any more.
But in some countries (eg China) these chemicals can be freely purchased. So, besides the profit difference in buying ready made tablets/powder, it comes down to ease of availability and ease of transport. However, getting them into a country like Australia is a different matter altogether.
This is why great effort is often made to conceal these chems as they enter the country. Customs are aware of them, and can test for them just as easily as they can for MDMA. But precursor chems like MDP2P (and freebase MDMA for that matter) can be 'hidden' by dissolving in solvents, making detection a bit more difficult. While customs have very sophisticated detection equipment, at present it would still be extremely difficult (I'd guess; logistically impossible) to inspect every drum that enters the country that contains a suitable liquid hydrocarbon or other solvent.
So, while profits for crime bosses are potentially higher by importing chems, concealment is still required. However, as time goes on and detection methods improve, there will be less hope of safe delivery. When it ceases to be statistically/ economically viable to import, producers will, in all likelihood, first source via local, non-related industries before eventually turning to sourcing starting materials from local raw materials.
Initially, I believe many starting materials will be sourced via other industries that use them. I have a colleague who works in a non-drug related and completely legit business, but it's quite amazing what chemicals he uses in his everyday work. I won't go into the work he does, but I will say that he has mentioned the increase in inquiries he gets related to some of these chemicals. Not being a drug user, he's still acquainting himself with what some of these chemicals are used for in drug manufacturing. Needless to say more stuff is stored in the safe these days. Although he doesn't sell anything to anyone he even remotely suspects of being involved in drug related activities, at present he is under no obligation to report suspicious inquiries to authorities (via EUD's - see above link).
But that day will come for sure. Then, we are likely to see crime bosses turn to relying more on the local, 'easy' to obtain products. Ingredients such as safrole will come from native flora or xenotype species, and the other chems will be purchased through chemical suppliers by legit businesses or individuals, as depending upon routes chosen, nothing suspicious would need to be ordered. The downfall is the time and steps involved, but IMO, once a setup was in operation, like most production line industries, these disadvantages would easily be offset by the continual availability of a cheap product. Such clandestine setups no doubt already exist. One advantage a proper setup would have, is that it could easily be 'adjusted' to produce a new designer drug if MDMA ever becomes 'old hat'.
While an optimized local clandestine setup and network may prove to authorities to be difficult to locate, the real dangers are to end users, as the extra steps required will invariably mean there will be more contaminants present in an end product.