Just because Agents of SHIELD isn't exactly what Marvel had hoped for doesn't mean they're done with TV series. In fact, it appears their upcoming focus will be in episode format, as they have already announced FIVE Netflix TV series based on Iron Fist, Daredevil, Luke Cage, Jessica Jones, and The Defenders, along with Agent Carter coming to ABC.
New reports from Deadline suggest that the series will skip the entire pilot phase of creating the show, and go directly into major production, supposedly planned to hit ABC after Agents of SHIELD's Season 2, in which it would air at the same weekly time as the Marvel show after the season's hiatus.
However, after the events of Captain America: The Winter Soldier, a show about SHIELD during it's early days along with the fall of SHIELD appears to hint at the show's conclusion after its first season. Could the show really be cancelled? Surely not, but with Marvel, anything is possible.
The series originated from a marvel One-Shot included on Marvel DVD release. Since then, the idea for a TV show and a script have been developed, and the show seems to be coming to fruition with the recent reports of it's speedy progress.