-Why not making a Minecraft-like pre-alpha buying method ? Why you will ask ? Simply because such a huge project needs Devs, maybe a team. Money is not everything, of course, but it will surely help this project to grow and becoming a long time project.
Do you suggest making SE paid? I think this is bad with current developement state. When I implement gameplay and server, it will be a good base for a paid online game.
-How many devs are working on this project ?
I work on the code alone. Some people makes models and help with textures and catalogs. Here is the list.
-Do you have a roadmap or something like that ? Do you have an idea of what could be the final product ?
Read these threads: