The issue with big publishers these days is that they want Payable DLC, Microtransactions, Paid this, Paid that, Yearly releases .etc
This type of game doesn't fit into any of that criteria, they might have pitched it and publishers simply didn't want to take the risk. They couldn't milk it after release and the amount of sales was uncertain.
That being said, I am excited for this. I haven't backed it yet but most likely will.