Building developer platforms is fun and exciting. Especially for the developers creating it, knowing that they are building a rockstar application for people just like them. Getting adoption and conversion to paying customers is so freaking hard and ultimately the end of the road.
I went down this road once (http://www.odatahq.com/) and loved every minute of it. I still look at what we made and find true joy in it. But the end game was typical of most developer platforms ...