The Microsoft low level API should have been released a long ago, if not with Windows 7, for sure with Windows 8/8.1. Microsoft made a decision to do that seeing Mantle’s efforts. They didn’t want to stay behind because the gaming industry is the most important sphere why Windows is so popular. Microsoft used the low level DirectX12 as a strong attraction for the people who play games. Don tell me you don’t see many people installing Windows 10 to have Directx12 only. Now, developers have a choice: two good APIs, where one is limited to one (or two) platform and the other is cross-platform.