To quote Bill English, author of the Administrators Guide to 2007
Bill English, an MVP from Minnesota who is weathering the cold and snow, predicts that the uptake for SharePoint Server 2010 will be slow in 2010 due to deep investments in 2007 implementations that didn't occur until the 2008-2009 timeframe. "Many will "kick the 2010 tires" in 2010, but will put off adoption until 2011 or 2012. The economy will need to improve to help fund upgrade projects.
English goes on to point out that few firms have mature enough Knowledge Management requirements to see the benefit of 2010.
2010 is a vastly superior product, but what I see again and again is this. Hey we have 2007, we have Windows 2003 32bit servers, we have paid for all of this and we know how to install it. We are not using 2007 to its full potential, so why invest more in the latest version.
Working with a lot of public sector clients this argument is pretty overwhelming in the face of 20% cuts in overall UK government spending. With the banking bailout and long recession meaning the rich and the poor are getting massive payouts from the states in Europe and the US its hard to see any government taking up the later version.
This probably goes double so for private sector. Private sector usually is even worse with information management and governance than the public sector, and the Enterprise Content Management features of 2010 will be hard to sell against the extra costs of converting to 64 bit and migrating any existing 2007 solutions.
So until the economy picks up a bit, which might be a year or so, I see most people playing it safe and going with 2007. Always remember you are a Microsoft consultant, people buy your stuff because they wanted to go safe in the first place! User conservative stances are pretty strong, how many people do you see not only using XP but still buying small XP machines?
Microsoft can threaten end of support, but even that is unlikely to change many people's behaviour. IE 6 is still around in many Enterprises and taking forever to get rid of. SharePoint 2007 may be the same thing, something we kind of regret having pushed so hard in a few years.