What free, opensouce, network operating systems currently exist that run on whitebox broadcom or other merchant silicon switches?

I know Cumulus is very popular, but I don't believe they have a free version that runs on whitebox switches right? Only on a virtual machine from what I can tell. 

I think if one of these vendors would release a free and truly opensource network operating system, with the option for paid support if needed, then whitebox switching would really take off. This would be similar to the Redhat model, but for the networking world. 

Right now, the cost of the whitebox plus a paid network operating system seems to equal the same cost as a discounted Juniper, Cisco, or Arista. I am not seeing the savings on paper. 

If we could just buy the whitebox hardware, and have a free operating system on there, then financially whitebox switches would be half the cost of a similar Cisco switch after discount.

Am I missing something?