Wrong on all counts: circumstances are exactly the same.
No starting money, expenses covered for top 4 athletes in CMAS and top 4 in AIDA...
This is not quite true. At least not for French CMAS (well, FFESSM) competitors, I do not know how is it for Italians, or other Med nations. The French federation FFESSM is quite supportive toward competing and rather generous, and we get financial support for attending practically any competitions organized by the FFESSM. You get the support from FFESSM even if you do not rank at all, and even if you are disqualified. Well, it rarely covers 100% of the costs, but it is certainly welcome. The members of the national team representing the federation abroad get much more financial, material, and organizational support, of course.
Then, also clubs usually have some funds available to help competitors with covering their spendings. Our club, for example has around 50 members, and only handful among them use to compete. So although the yearly fee covering the federal license, pool access (5 hours a week), insurance, dedicated life guard, sofrology courses, and other expenses, is quite moderate (below 200€), there is still enough remaining to support couple of competitors.
As for AIDA, it can be certainly done too. All it takes is couple of skilled, willing, and communicative persons on the level of clubs, and national AIDA branches. Increasing slightly federation and club membership fees, contacting companies for sponsorship, offering them advertisement during competitions and on websites, contacting municipal and regional authorities for some funding, and for access to their pools and facilities - all that can be done, and can generate moderate but sufficient amount for funding not only attending and organizing competitions, but also for training. It is exactly what our club president does. Similarly it works then on the departmental, regional, and national level in the federation.