Why GNU Hurd Never Got off the Ground
- Idealistic. Did not join the worse is better philosophy, ie, it's not the best but works great approach of Linux. 
- There are many open source projects like this - some neat features, somewhat incomplete, worked on by a small but devoted team. HURD is just a very high-profile example. This is a relevant point for OSE. A point of traction must be reached at one point in order to become immortal.
- Worse is Better Philosophy - implementation simplicity is key, not interface simplicity.