[nowherebeen]

Completeness isn't just about cross platform. It is just one example.

Completeness can also mean content. If your shopping app doesn't have vendors, no one is going to use it. Try getting vendors to join your no-name shopping app and I bet you will be 100% ignored other than desperate mom and pop shops.

And for games, it requires a huge investment of talent to develop, and very few games succeed. So completeness here would be getting game designers, graphic designer, software engineers to work together for low pay and high possibility of failure. The only games that don't require huge investments are puzzle games like tetris and 2048.

Completeness is the bar where the end users feel there is sufficient value to use. If Uber Eats only had 10 restaurants, very few people would ever use it. So the bar is very high to get people to start using it consistently.