I have no interest in continuing a fight that is clearly about your distaste in Windows 10 and not about the game in any way, shape or form, but I will leave these final words from me:
My friend does rendering tech at Tt Games for DirectX 9 and DirectX 11. Day in, day out, he's constantly working on it. Making tweaks, changes, optimisations, bug fixes and all kinds of stuff. His hobby, outside of work, is making a custom, personal use renderer. The entire thing is literally just a renderer. It takes a single model and renders it out via DirectX. He's spent ages on this loving thing and it's far from done.
Renderers aren't some tiny bit of code that you spend 10 minutes on and WHAM! you're all done. The renderer is the very core of the game engine, and it sets up how and when other parts of the game, such as scripts, physics, audio etc are able to communicate in. The renderer is also responsible for communicating with Windows directly. People don't just do rendering engines after being a general programmer; you have to specialise in it.
I feel like you're in the same position I was in when Halo 2 Vista launched, and I was firmly a believer in XP. The big difference here is that this is a game using very new, state-of-the-art tech (Halo 2 Vista's only Vista-required feature was that a single level needed to address a 64MB level cache to RAM which wasn't possible in XP; the XP fix program basically intercepted the call and then sent the file as two chunks, and then handled communication between RAM and Halo2Vista.exe during that level) that very few people have touched and that people are absolutely adoring right now. I'm really sorry that you can't be a part of it, but you made the choice and you live with the consequences. I know far more people who enjoy and love Windows 10 than those who don't, and this game is just the icing on the cake.
Very excited to give the Top Gear track a trial tonight. Just going to finish some programming stuff and then I'll dive in.