One of Green Arrow's main problems from a commercial standpoint (which he shares with a bunch of other mid-tier superheroes, and Wonder Woman) is that he doesn't come with his own sprawling mythology of supporting cast, villains, concepts and locations. People might pick up Batman not just for Batman, but because they want to check in on Alfred, Joker, the Bat cave, Gotham City, Two-Face, one of the Robins, Blackgate prison, the Batwing, James Gordon etc. Green Arrow has... Seattle, maybe? A few very loosely defined and intermittently used sidekicks? And a really shaky rivalry with Deathstroke?
Lemire had something interesting going with the Outsider clans, Diggle and Emiko, but those concepts would have needed to mature over a long period of time rather than be (mostly) thrown out for concepts that worked in a different medium. Now there's a new creative team trying to add new stuff without building on what's come before, and soon we'll be back to square one again.