Five years is too long for any product cycle and SQL Server will suffer for it. There are a number of reasons why five years is a problem. First, technology changes so much that your original goals become invalid. Second, competitors don't stand still. Finally, Microsoft is going to make anyone who purchased Software Assurance really unhappy because the Software Assurance only lasts three years.
So those people spent money with the promise of "next version for free" and got nothing. Unlike Office, Exchange, Windows and other major software which delivered a new version (or two) during the first cycle. I expected an offer of automatic SA extension for SQL Server until the next version but instead the product manager said that it really wasn't a big deal. Easy for him to say.