I think Ultimate Guitar has a lot to do with this.

Sure, G is probably the most popular chord, but there are a _lot_ of chord sheets that are wrong or incomplete. If someone were to play many of these songs as charted on UG it would sound unrecognizable.

Kind of invalidates the analysis IMHO

And how many charts call for a capo to be used so the performer is using key of G chord shapes but actually playing a different key entirely?