That's not a bad idea... we just don't have plans to split the sites yet.
I understand that you don't want to split up anything, but how about mentioning the OpenSource version at all? 🙂
Right now, when I go to nodebb.org, the only chance to see that there is a free version that I can roll out myself is to know what the github logo looks like and then scroll down all the way to the bottom to spot it there (very small, barely visible).
Additionally, if I have AdBlock Plus turned on, these social buttons do not appear at all.
I perfectly understand that you want to earn money and therefore want to focus the page around your hosting service but I think that you could significantly cut the amount of requests from people who heard about a cool OpenSource forum and who now struggle to find a link to download it.