I agree with you, I am also very disappointed as I was very much looking forward to playing the (Forza motorsport/horizon) games on my PC with my T500RS wheel. It is shocking that a modern racing game like Forza will lack steering wheel support. games like PCars, Assetto Corsa, The Crew, Dirt Rally and every other racing game on Steam for the PC supports virtually every single steering wheel and usb peripheral on the market. for this to be an omission on Forza shows a complete lack of understanding of the PC gaming market from MS. MS has failed the xbox one to Sony’s PS4, and failed the Games for Windows/Windows Store to Steam and now it finally has a chance to redeem itself, claiming it wants to take PC gaming seriously yet here we see MS once again making very poor decisions that will turn away customers to its competition.

Getting Started with Windows Drivers - Windows drivers
Windows Drivers allow you to create one driver that will run on all Windows variants.