From the article:

At the heart of the global effort to improve educational attainment is a contradiction. Everyone supports the idea that providing quality education in developing countries is beneficial, but funding by both governments and aid donors continues to fall short.
John McArthur, a senior fellow at the Brookings Institution, describes education as the “super apple pie” investment. Funding learning helps achieve many of the sustainable development goals that UN members signed up to in 2015. On current trends, however, spending will fall well short of achieving those objectives.