Lay-offs :(

It probably hurt sales, but the episodic format worked really well for Hitman in the end. Most players would say it made the game better, eventhough none of them, myself included would have believed that up front. I think the online only DRM also hurt it. The large number of early bugs and missing features. The somewhat "soft" gameplay compared to previous more edgy games in the series. And SE just expecting sales to be too high as usual.

At least some good news about the whole situation: Square Enix is willing to also sell the Hitman IP alongside IO Interactive http://www.eurogamer.net/articles/2017-05-30-square-enix-willing-to-give-up-hitman-rights-to-ensure-series-future
Should make buying IO a lot more attractive for other publishers.

Pretty gross the way SE fucked this whole thing up. And boy did they. I read a good article on it, but can't be bothered to find the link.