I examine video evidence for a living. This isn't bad. In fact, it is better than most I've looked at. If you could have gotten the media to play it, chances are, someone would recognize the suspects. At the very least, a media release on the vehicle and stills of the suspects could be posted and circulated in the neighborhood.
I can related to having a caseload of 100 cases, but you can't look at it that way. 1 case with good leads can break a dozen cases. If the suspect sees himself at locations around the area, he'll at least move on to another area. If you can't catch him, then at least make him someone else's problem.

I've seen many other Dallas detectives work very hard with a lot less information and leads to make a case when frankly, they were grasping at straws because that was the job.

It's easy to forget that because you can't see a license plate or identify a face that there are other parts of the video that are useful.

Send that video to the sergeant over that unit and make some stills and get them distributed in the neighborhood with a decent reward.

[Ed Note: Too late... they've decided they aren't going to be able to identify the people so "case closed" unfortunately.]