It seems to me quite unlikely that someone will buy only the software and not the hardware, I believe that most of these systems will be installed by some vertical company that will sell both hardware and software. And I honestly don't have the knowledge, nor the capital, to set up a vertical company around (say agriculture).
It ends up to understand what should be my customers and I am afraid they won't be the final user of the system.
My customers are technical, I provide them with digital data that they should somehow consume and it is not an easy task...
For many companies the sales channel to this might be the it agency (postlight type of company) - so I would suggest selling your expertise to these guys first.
What you mean by postlight type of company?
I think your segmentation is way to rough. There is a ton of space between the farm with a few hundred nodes to manage, and Nest with a few million nodes.
People are just learning best practices to manage a few thousand web servers. Managing a few thousand brickable devices with KBs of RAM is more challenging.