DirectX 10 and 11 are part of the OS and there are no standalone installers anymore. What Steam does is noticing that the game has a dependency on DirectX and i

DirectX 10 and 11 are part of the OS and there are no standalone installers anymore. What Steam does is noticing that the game has a dependency on DirectX and it launches a stub installer but apparently cannot actually check whether it runs on a recent Windows version where that thing does essentially nothing. There is a DirectX-9-compatible layer in current DirectX.