Combined with the WTMD, I think the "idea" of the puffer would have worked very well to detect bombs. Maybe include a puffer type system to also auto-puff stuff that went through the x-ray would work well too.

If the TSA said they wanted to stay on the puffer route, I think that other manufacturers would emerge, providing higher quality and lower maintenance devices. I imagine when they made the first WTMD, they also had a high maintenance/operation cost too.