Ebola isn't like most people think. It isn't airborne, isn't respiratory and requires direct contact with blood/semen/feces/etc to spread. It's also only known to be contagious once symptoms are present. The risk of a global outbreak is very low.

Africa has a large array of unique circumstances that make it much more 'viral' there, including various cultural funerary rituals that involve contact with corpses that can have extremely high viral loads, bushmeat consumption/processing (ebola can spread from animals to humans), as well as all the more stereotypical (and accurate nonetheless) reasons as well that make it particularly dangerous for healthcare workers there.

It's not entirely clear how it could spread uncontrollably outside of Africa.

I think that’s going to be true if any disease whose previous outbreaks were only in a “third world” place. The rest of the world easily ignores it. If it was contained but in let’s say - some European country - I bet it would be in the news 24/7 still.