Machines don't make decisions; software does.
Define "decision." I don't see a principled line between the sorts of decisions that software can make and those a physical machine can make. Consider for example, the old electromechanical phone switches....
Machines do not adapt to their inputs; software does.
Again I am not sure what this means. Maybe it could use more explanation?
Machines do not prioritise their responses to inputs; software does.
Why not? Certainly I could imagine a machine which would prioritize processing of inputs.
Machines have physical limitations; software has only logical limitations.
I think I get what you are saying here but I am not sure what relevance it has. Certainly the system running the software has physical limits. So software is a sort of abstraction and being an abstraction allows us to think about it disregarding the limits (I think that's dangerous though). But I think there are also human limits to software and because software is an abstraction we don't tend to talk about those.
Bottom line: Software is to hardware as pheromones are to ants.
That's actually a good analogy. I like it. But pheramones are subject to physical limits (temperature, air characteristics) etc. right? ;-)