AMD doesn't have a lot of money for R&D, but they compete fiercely to setup a future where their intrinsic hardware design choices will shine. It's been years in the making, but as soon as the next-gen console APUs were being developed, it provided AMD a huge opportunity to change the course of PC gaming.
How best to get the ecosystem to benefit their hardware? By building the foundation of next-gen APIs and giving it away for free. First to Apple with Metal, then to Kronos, this forced MS into action because these are the biggest threat to the Windows ecosystem (DX). MS rushed DX12 so much the programming guide was lifted, entire paragraphs, from the Mantle programming guide that AMD wrote. They had to get it out first and not come behind Vulkan, but it was possible to come from behind, since Vulkan is cross-platform, with a lot more partners all with an interest so it's development took longer than DX12.
Yet here we are today, and I hope Vulkan is the future, it is open, cross-platform and no UWP restrictions. It needs big players to champion it, get into Unity, Unreal Engine, the popular indie engines. But it looks like Vulkan will lose to DX12, with most of the AAA titles upcoming confirmed DX12 rather than using Vulkan.
Since Polaris is confirmed to be in next-gen consoles, anytime somebody ask for advice on future proofing, you have to be completely ignorant to even suggest that NV GPUs are more future proof at this point. Certainly after knowing more about DX12/Vulkan and it's roots.