"Future Proof" is a myth in PC hardware. It has never existed and most likely never will.
I think back to a member here who, around 8 years ago, proposed a build with 4 Maxwell Titan X which was almost $5,000 in GPUs alone. He said he wanted to build a beast that would be future proof for at least 7 years. SLI died years ago and most people didn't see it coming but it did come. Another member bought a Titan Z for $3,000 and complained because of lack of support from Nvidia even during the Maxwell series. He said that he expected Nvidia to give the best quality support for his Titan Z for at least 10 years because of the price he paid.
Who knows what the future will bring but whatever it does it is certain that it will make today's hardware obsolete and puny in comparison.