> There is another, I think different, form of "source available" that I've seen a bit lately, similarly from corporate/commercial sponsors: the source code is released under an OSI approved license (e.g. BSD, GPL licence) and the owner maintains and develops the code in an ongoing fashion, but there is no way to easily interface with the developers, contribute changes back to the project, nor is there any public facing bug tracker or developer/user community. To me this is just as much "not open source" as a specific no-compete with the primary project sponsor.

No, that's very much open source - in fact, it was the way most big name open source projects were developed back in the early days. See the famous "the cathedral and the bazaar" essay. Public bug trackers and widely soliciting contributions to mainline are relatively new phenomena, but you always had the right to fork and maintain and share your own fork, and that's the part that's essential.