I'm also highly in favour of open-sourcing, but I'd say it's a balancing act between how much value the project provides to Hive and how certain it is that it won't just be abandoned (i.e. is it just code or is there a real company behind it?).
Imagine Splinterlands would have asked for funding, them open-sourcing their files could have made it difficult to prevent copy-cats from popping up. Code is still intellectual property and I personally wouldn't release it unless the position of my company/project is established & secure.