I'd say it's this, but with a couple more thing. One is a lot of experience with the tools they are using. Not having to learn something new saves time. The oth

I'd say it's this, but with a couple more thing. One is a lot of experience with the tools they are using. Not having to learn something new saves time. The other is not over-engineering. They have a great idea of the scope and scale of the project, and avoid programming for things that would be out of scope.