Google doesn't manufacture ereaders, phones or tablets. It sells a mobile OS and it's the proprietor of one of many app catalogs for Android. It also has little control over which ereader apps are shipped with Android devices (except for the one Samsung model they sell).
As for its ebook store: they launched it less than two months a go; it's impossible to tell what their plans are. Outside of the US, they only offer books that are in the public domain. Even within the US, they don't seem very interested in selling ebooks: 'Google eBookstore' is only one of dozens of available retailers within the Google eBooks app.
