Exactly. Until Google Drive(/Docs?) integrates all the features of MS Office or comparable high-end suites (which is a long way off), a Chromebook doesn't actually serve the needs of the average user. Sure, it works for a casual user that just wants to surf the Internet, but a lot of people can't do what they need to without a variety of third-party programs.
I wouldn't consider myself a "computer junkie" or anything, but I could never use a Chromebook as anything other than a backup PC -- when I got this new computer, the first thing I did was install LibreOffice (which is between MSO and GD in terms of functionality), iTunes, Spotify, Skype, and a host of other programs that I use just often enough to warrant their installation.
And the thing about Chromebooks is that because they do have a niche, and they occupy it very well, Google doesn't have all that much incentive to develop them into full-fledged computers. When people are buying enough to secure your profit margin, it's very hard to justify the sort of extensive development that would be required for a Chromebook to replace my PC.