If this
http://gamejolt.com/games/the-joy-of-creation-halloween-edition/202196
Was created in 2-3 weeks, cinema would be created in like 1-2 weeks
most of work would go for maps
Also it’s mostly because of this
[/quote]
That’s a terrible comparison. That’s just a short single player experience with no fancy or complicated features. For a cinema gamemode, they’d have to make all of the maps, implement the screens, implement the YouTube API, set up a few servers for it, implent some moderation features. Tons more would go into a Cinema gamemode then that game you linked. Could potentially take months to make.
EDIT: Oh and as for you’re second point, that’s why this exists: