I find that if 'future proofing' is defined as buying the best available parts today and keeping the system for 5+ years without upgrades, then it is a waste of $ and time.
Personally, instead of buying a $500 cpu + $200 mobo + $500 gpu, I'd rather get a $200 cpu + $100 mobo + $200 graphics card, sell that 2 years later and buy new faster mid-range parts again. I keep using this strategy while ensuring that my total out of pocket upgrade costs do not exceed more than $250-300 every 2 years or so. In the end, I end up with a faster and a cheaper system for the majority of the 5 year period compared to that futureproof system which in 5 years is worth $150 at most. I equate future proofing to buying a console at launch date and letting it age for 5+ years, while my system continues to evolve every 2-3 upgrade cycles in the same period.