Why did MS chose Windows 10 instead of Windows 9?

Microsoft has unveiled the next new Windows, and surprisingly, instead of Windows 9 we would expect to follow a Windows 8, we got a Windows 10! Several theories quickly flooded the internet, but the one that seems the most credible tells us this was done to avoid compatibility issues with poorly coded programs.

Windows 9 leak confirms Start Menu and virtual Desktops

Microsoft will unveil their new Windows 9 in the end of the month and provide a "Windows Technical Preview" that will allow for a rapid development in the coming months, in preparation for it's launch next year. But once again, secrets are hard to keep, and images and videos of the Windows 9 technical preview are already available in the internet, showing us what to expect.