Microsoft took a huge risk by releasing an operating system that didn't look, feel or operate like any Windows version before it. At that time, Windows 7 was only three years old.
Windows 8 was built for touch so that it could be used on a tablet as quickly as a massive gaming rig. People didn't respond to all of the changes The tile-based interface was confusing and unfamiliar, the Start button was missing, and the Windows Store was empty save for some questionable applications.
There was a problem with Microsoft that needed to be solved above all else. The operating systems were designed to work on both tablets and non-touch devices. Those without a keyboard and mouse couldn't use the desktop interface if they didn't have a touch screen. The ability to boot directly to the desktop was solved by Microsoft. The damage had been done and Windows 8 would be replaced by Windows 10.
Another failure was Windows RT. The lightweight version of Windows 8 for tablets was limited due to its dependence on the app store. Third-party makers of tablets decided to put the full Windows 8 on their devices after skipping WindowsRT.