They are, sometimes better than them, sometimes worse, depending on the generation. But in general they are at least as good.
The difference in securing the qualifications is that these top African teams are strong favorites in their groups, while Sweden, Croatia and the likes always have France, Italy, England, Holland, Germany, Spain or Portugal in their groups, plus dark horses like Slovakia, Bosnia, Ukraine as 3rd pot teams in the group.
But the qualifications are very hard both in Africa and Europe, as Snoop said. One bad period, both in Africa and Europe, will almost surely mean an elimination, because only 1 team qualifies from a group in Africa and only 1 team qualifies directly from the groups in Europe.