Despite mandatory SEC filings, the media companies that Faultline keeps tabs on remain very opaque. The larger they get, the more secrets they keep, by and large, and so digging into the recent cancellation of Batgirl at Warner Bros. Discovery led us down many rabbit holes. The chief revelation has been the disparity between the content spending among SVoD services, with an insight into the ROI modeling that these services obsess over. Our sister service, Rethink TV, has some numbers to hand – although it notes that so much ground has shifted in the past six months that it will be revisiting its SVoD predictions in due course. We have added in the projected content spends for each, across their…