Well it looks like Windows 10 could be it. The idea is to add an HDMI monitor, a keyboard and a mouse to your Windows Phone and you will be able to use it like your laptop. Applications that work on your computer will work on your phone, Office will look the same, Outlook will look the same. You'll even be able to use the screen on your phone as a track-pad. There will be a gesture for moving apps from your phone to the big screen.
There had been some speculation that this would require new hardware in order to work well, but Microsoft has demoed this capability and it really looks good using Miracast/ScreenBeam to display the phone screen on a monitor. For casual users, this could be your new laptop. The technology that makes this possible is called Continuum.
There are some restrictions using this Continuum – you can only run one application at a time on the big screen, though you can still run a different app on the phone screen. You won't be able to run legacy apps this way. There will likely be other differences because of the phone functionality.
Currently I've got a Consumer Preview of Windows 10 running on a Nokia 1020 and a touchscreen laptop. It's neat to see that they're converging these two platforms - this might just save Windows Phone.