Given that Microsoft spent $2 Billion on helping Dell go private again I'm surprised at the lack of a Dell 'built for Windows 10' PC launch.
Dell themselves could do will the boost and having a platform built to make the most of the OS would have made sense for Microsoft I'd have thought.
The free OS update approach is odd from a company who makes money from software. It always made sense for Apple for who shifting hardware was their goal but for Microsoft it seems to be a desperate attempt to restore credibility which may work if Windows 10 is good but ultimately puts them in a difficult position because doing this sets a precedent and users are going to expect future updates to be free too.
I can only imagine this is to keep users on Windows so that they can continue to sell Office 365 subscriptions.