Some "dumb questions"...

- You qualified for budget and buying authority...did you qualify for Need/Want?

- Did you...Ask For The Order...after the demo??

- Have you found out why they didn't buy after the demo?

- Did you discover if they had seen anything similar beforehand, or if this was their first look?

- Did you give them an Expected Next Step, announced before the demo?

My suspicion is that you educated them, and then they went off to find what you offer at a lower price or with better features...now that they're all educated on what to look for.