I think that was one of the ideas behind Lego Worlds, originally. It did end just as a sandbox, but I believe originally it was going to support scripting and sharing of games - with the idea being that Lego might pick up the most popular of them for standalone release.
Somewhere around the 2015, the beta releases dropped the capability. (Along with infinite landscape.)
There was some rumours about Blockland maybe threatening legal action if they kept it, but nothing concrete, so take it with a grain of salt.
I never heard of block land, I just looked it up, watched this YouTube video about abandoned multiplayer games https://m.youtube.com/watch?v=1FEW7gxci2Q . It was a bit sad to see it in such decline. It reminded me of a non commercialized version of Roblox.
Somewhere around the 2015, the beta releases dropped the capability. (Along with infinite landscape.)
There was some rumours about Blockland maybe threatening legal action if they kept it, but nothing concrete, so take it with a grain of salt.