But it is weird that we don't see better open source games, because good storytellers have no problems giving their work away for free. There is an overabundance of great writing on the internet. But taking a solid plot and turning it into a game engine just doesn't take.
I'll point at Return of the Obra Dinn as a nice example I played through recently. Very simple story (ship suffered a terrible fate), very simple mechanic (figure out who all the passengers were from visual clues). Individually all the ideas are so trivial it barely makes sense to talk about charging for them, and the engine isn't so amazing. But I've simply never seen an OSS game with that level of quality and storytelling. Which is actually highly weird given that I've seen both better quality storytelling and engines of similar or higher complexity made available as open source/free as a labour of love. There is something much more interesting than meets the eye going on in game development to do with the intersection of GUI complexity/difficulty of asset creation/stories.