Yeah, it depends on the specific thing you want to do. Sometimes one person is enough for the whole project. Sometimes one person is enough for making the most simple version of the project; and if others are impressed and joined, they can make the project greater, but their participation is optional. But sometimes you need a team to create even the smallest version of the project (either because the project is too large in scope, or because it requires many different specializations).

Not being able to cooperate limits a person to one-person projects; and only those where they have all the necessary skills.