Taken in isolation Google Apps is not that much. It's a Microsoft Office clone, delivered online, which you can rent instead of buy.
But by placing it online, and through the miracle of open source, it can quickly become much more.
When you expose your code to the world, you expose yourself to all sorts of organic growth, growth which can support your own efforts even while it seems to drain away revenues in various outside niches.
Google Apps is a more powerful solution with a CRM, even if Google didn't make it. What else might you make which Google hasn't?
Extra credit question, for those over 30. How would you compare the growth of this open source enhancement ecosystem to that of, say, Microsoft in the 1990s or the IBM PC "back in the day?"