There are 53/54 countries in Africa so I won't pretend to generalise to the continent. I do know a little about some of the countries in Western/Sub-Saharan Africa.
Its true that many nationals from these African countries, especially when trained abroad tend to stay abroad. (This is less severe in Africa than the Caribbean by the way) This is especially true when the country is stagnant politically and/or economically. There is serious research that also indicates that if these same graduates feel that there is progress and hope, many will choose to go back after their studies or their work terms abroad. In cases where, after years of stagnation/repression, once there is regime change, there are a significant number that tend to return (I'm thinking of countries such as Ghana and Mali). Many will give up lucrative careers and lifestyles to "make a go of it" back home.
When the West had very limiting immigration options (up to a few years ago), often getting there through an educational program was the only way out for many in the developing world. What started out to be a exercise in training locals to build capacity turned into an institutionalised brain drain of the best and brightest.
It still goes on but the "West" has realised it needs skilled immigration and so it is easier for many to apply without having to go through the "scholarship" program first. They know they can essentially apply at any time. There have also been a number of legitimate regime changes, particularly in Africa with significant political and economic progress in the last 15 years. So the skilled have options, its the unskilled that tend to try the illegal route.
From experience, I've found that hope, or at least the perception of opportunity (as opposed to the level of absolute wealth) is the best motivator. Countries I have worked in where there was legitimate hope, even if very poor, had a strong retention and return rate. and this of the "very bright".
The "NGOs" or Non-Governmental Organisations are an interesting group. (I used to work for several back in the 80's). They are a mixed blessing (and a mixed bag). Many recognise that to be successful they have to work themselves out of a job. Many do and have their programs taken over by homegrown "sister organisations" that they in turn continue to fund. Others look to this kind of work as their only "raison d'Ítre" and continue to pursue a limited program of dependency.
As I mentioned earlier, I find the "bright" Jamaicans and Guyanese (in particular) who have left, to be the harshest critics of their countries. I think this is mainly out of a sense of frustration, simply because they know what "could be" and then get very frustrated by "what is" and they have little or no power to change it so they essentially slam the door.
On a lighter note, you must be able to get the Jamaican patties somewhere in Dallas. Heck, they've become so popular in Canada that we can get frozen ones in boxes at Costco!
For the red stripe, I prefer mine with jerk chicken and pork while listening to some Reggae on the beach and getting e-mails from co-workers, friends and family complaining about the snow storm that dumped 12" of snow....again.
Now based in Barbados.... and wait for it.....the boat is too!
Waymar - Jeanneau, Attalia