The point of the message is to encourage Jeffrey Sachs and Bill Easterly to put aside their disputes on the lesser topic of aid effectiveness, and co-author an essay on a more important subject about which they appear to be in agreement: namely, what actually works in global development.
Dear Professor Sachs:
I have been greatly heartened to hear directly from you, and from Professor Easterly (cc'ed), your shared view that entrepreneurship and innovation are at the core of the process of economic development. The two of you may also a share the view (one that I hold most emphatically) that a development strategy focused on entrepreneurship and innovation is not equivalent to one that relies on markets as they currently exist. Rather it is one that considers interventions to markets strategically, with an appreciation for the reality that solutions in a rapidly changing world are not known, but are rather are evolving, and thus that success at scale begins with broad-based local experimentation combined with the resources, commitment, and alignment of incentives that jointly ensure support for approaches that work.
I believe that the discourse on global development would be greatly advanced if you and Professor Easterly were to participate together in an event, and jointly author an essay, focused not on the subsidiary subject of aid effectiveness, but rather on the core issue of what actually drives global development--a topic on which it appears your are largely in agreement. The event would be all the more interesting if you could be joined by actual entrepreneurs who have, in their own work, advanced global development--people like Iqbal Quadir and Mo Ibrahim. Should you be willing to participate in such an event, I am sure that you would find any number of willing hosts. For my own part, I can say that Innovations journal would be more than pleased to publish the jointly authored essay that the two of you seem well placed to author on this topic.