I have a slightly different view on this. I think that the other BSDs have a fundamental development problem: -current is often broken.
If I notice a bug in release, I can grab a snapshot and download the source and write a fix. This is something difficult to do with other BSDs. Also, the systematic peer-review of diffs before they get committed reduces the possibility of buggy commits. Users can speed this further by testing diffs on -current. If other BSDs worked this way, they would have been successful in attracting a larger userbase. They have the means to do it with their larger developer community.
