my understanding of the situation is the same as
/u/notevenjk-lol - James Hewitt was the original writer of the rules but he knew he was going to leave so gang war 1 was not his best work. He was serving notice during the writing of gang war 2 which is why it is a pretty useless book (mentally he had checked out which many of us can understand having been in the same position). It is also why, despite him having left the company at the start of the year, James was doing ama's about the Adeptus Titanicus rules which he had written a year before (and to be fair to him are very good).
JTY was hired as his replacement for gang wars 3 and 4 which are a big improvement. A lot of the problems were fixed (typos, layout, contradictions). Rules that were not properly playtested like the original campaign system were also given alternatives like Dominion.
Whilst I have no doubt that GW are capable of decisions to increase revenue by writing 1 book and splitting into 6, in this case I believe it was just down to them being behind the curve. I expect that we will see many things in the comoendium that corrects prior books in a way that makes it unlikely that this compendium was the original document all along.
Of course I could be completely mistaken.