According to the real definition of future-proofing, no processor is future-proof. All of their specs and technology will fall obsolete at some point. However, we can talk about comparing durability. This would be how long can a processor last compared to others. In that case, an Intel i9 is more durable and “future-proof” than any other Intel CPU, due to how strong and fast it is built to be.
The other side of the coin is AMD. Team Red decided to ban the previous gen, like DDR4 and AM4 motherboards, with its new AM5 socket type. This helps technology advance and closes “future-proof” ideas from previous-gen components.
It has to be remarked that, every time the PC components are growing stronger which makes them more durable and delays their planned obsolescence. However, it always gets the time when they just aren’t enough. At the moment of writing this text; it’s clear that an Intel i9-11900K, a 2-year-old CPU, is already almost useless; with only 8 cores and the socket 1200 that no motherboard uses anymore.