As it stands, they'd need to see a total catastrophic collapse of the economy of most of the African continent, with no subsequent recovery, for economic growth to not outpace population growth over the next few decades.
I'm sure you can't extrapolate it and assume it will stay the same for the next 30 years. But you can make reasonably educated estimates assuming that the average change in velocity will be all that extreme, given that large part of these amounts are based on income from relatively stable industries with well understood risk profiles.
Largely the development of Africa at present boils down to whether or not we see further major wars disrupt the progress. If we do, then, yes, things may go the wrong way. If not, it will take unprecedented crises to prevent Africa from continuing to see massive growth.
> But if I was a young african male, I would try my luck in Europe.
If you were a young African male with the means of getting to Europe, there's at least half a dozen African countries where your economic prospects over the next 20-30 years would likely outstrip going to Europe unless you are in a tiny minority with skills that are in very high demand in Europe.