They're attempting to bridge the gap between a tablet and PC using 1 operating system. If played right, it could be a huge advantage to people really only needing one device for everything. You can see this in the new OEM devices coming out (ASUS Transformers, Samsung, etc..)
Why would I want 2 different operating systems if the underlying goal is to reduce the complexities of needing 2 devices... one for 'play' and one for 'work'?
Because sometimes you want different operating systems for different purposes? Presumably you don't want a phone OS running on your website servers, and you don't want a server-optimized version of linux running on your phone.
My phone is supposed to be good at calling, texting, and browsing the web on the go. That's a much different purpose than my laptop, which is meant for coding, etc. So doesn't it make sense for them to have different operating systems?
There are different operating systems, or at least different use cases built into the same operating system. Sweet jesus, I have to abandon the Internet for the next few years until people realize the world didn't end with Windows 8. It's frustrating to see such uninformed words being written and accepted as fact by such otherwise incredibly intelligent people.
A different OS for a server than you run on a phone? You mean like the difference between Windows Phone 8 and Windows 8 Server? Because it's a huge difference. Not even comparable. You're saying you can't code on a Windows 8 laptop? How am I running Visual Studio 2012 right now? In another window, I have an SSH session open to my VPS, editing some Golang files.
Here's the problem: Microsoft is basically giving you a free iPad bundled with the update to Windows 7. It doesn't hurt anything to have it there, but for a great number of people it really helps. Those people will likely never see the desktop, never care that it's there, and that's exactly what they want. For people like you and I, the only time we'll see Metro on our laptops is when we boot and when we hit the start button to search for a program via keyboard. The desktop is still there. It hasn't changed except for getting better. And yet people still seem to want to turn it into a negative with hyperbole, FUD, slippery slopes, and sometimes even outright lies. The world has not ended. It hasn't even changed. Window is Windows, your phone is a phone, your server is a server, and you still complain.
Why would I want 2 different operating systems if the underlying goal is to reduce the complexities of needing 2 devices... one for 'play' and one for 'work'?