While we've been dealing with Ebola for decades, it was characterized as both a highly sporadic and largely self-limiting disease, and not particularly endemic.

While we've been dealing with Ebola for decades, it was characterized as both a highly sporadic and largely self-limiting disease, and not particularly endemic. Horrible as it is, that's not a great target for a vaccine. Especially not an expensive, hard to administer one. So it remained largely of academic and specialized interest. The recent Ebola outbreak was a recontextualization of Ebola, from a sometimes scary disease where it would be handy to have an infrequently used vaccine for special circumstances to "This might be an endemic disease in West Africa". Yes, throwing money at it helped, but it's hardly the only reason priorities shifted. I'll also note that there's promising work on Dengue Fever vaccines, which are third world diseases, and most of the diseases that are near-term eradication targets are third world diseases. Often these challenges aren't "Pharma hasn't developed a drug yet" but "How do we get this drug to everyone?"