It's a smart price but I suspect that Microsoft has burned too many bridges for most people to ever consider upgrading their computer's operating system. For the average person a (Windows) operating system upgrade has traditionally been cost prohibitive and often not a smooth process. That's going to scare a lot of people off even at $39.99 I'm also not convinced Microsoft has found a compelling way to sell Windows 8 yet. There's no one button buy/install option here. People will have to go seek out the software and justify the price tag to themselves. That's going to be an up-hill battle. I'm betting the percentage of users upgrading will be about the same as previous Windows releases.