[A]lmost every country in Africa has a low tax/GDP ratio. If low taxes were the primary key to growth then Africa would be far richer than it is.
I'll agree with Matthew Yglesias: this highlights the importance of a well-functioning government. It doesn't mean that low taxes don't help development. Recent work suggests that low taxes are a symptom of a bigger problem: a poorly-functioning formal sector. If taxes are at even a moderate level, then people in the formal sector will leave because the formal sector doesn't add much to their bottom line, anyway. Governments have to keep them low to get any tax revenue at all and they make up that difference is massive amounts of inflation. Show me a low inflation, low tax country and we'll talk if the role of low taxes in development is overrated.