Complex sentence: This was a very broad notion of the role that the independent companies would play, and there was considerable confusion over how these units would be used; for a while, this uncertainty threatened the very existence of the independent company concept.
Split into simpler sentences: This was a very broad notion of the role that the independent companies would play, and at the time there was a certain amount of confusion about how these units would be used. For a while, this uncertainty about their future threatened the very existence of the independent company concept.