A great example of this is djangopackages.com. Looking at thumbnailing packages[2] even though there are a dozen packages, only three are popular. And taking a glance at the commit sparklines only two are under active development. So I know to start with them.
It's rare to see a GitHub-hosted project that offers proper releases, proper planning for those releases, proper documentation, and the organization and project management efforts that enable such things.
The lack of such basic project management structure leads to projects that see very erratic development, or outright abandonment. Many GitHub-hosted projects are barely more than a hobby, rather than an ongoing concern. Their code may be somewhat usable, but it's rarely comparable to what we see from more organized projects.
Those projects do not get erratic development or get abandoned because they lack "proper planing". That is reversing cause and effect. They lack heavy planing because their development depends too much on free time of one or two people, who have other life priorities. No amount of planning will change that.