While the link is strong, poverty isn't caused by illiteracy & many other factors need consideration
The issue of poverty goes far beyond literacy and literate people are still involved in some of the worst living conditions in the world, especially when involved in regional humanitarian crises. The literacy rate in countries such as Syria and Ukraine for example are high, however due to conditions of civil unrest in these countries many people have become impoverished. Furthermore, there are many former soviet states that, despite having a high rate of literacy, have a high proportion of citizens living below the poverty line. Moldova, Kosovo and Albania join Ukraine as some of the poorest and most poverty stricken countries in Europe, despite all having a literacy rate well above 90%. There is a link but literacy is far from a fix all solution to poverty.