There are a number of possible reasons, but none matter if the...

There are a number of possible reasons, but none matter if the tech works and they can prove up the concept with strong results.

The markets bad, people are cautious with new tech. Trust needs to be built up that the walk matches the talk.
Also, industrial start ups are possibly not as exciting as say a copper or gold discovery.

It's altogether possible that once the US roadshow picks up there will be a sharp rally. It is still very early days. We certainly haven't seen this info fully play out in the market as yet. imo.