I'm of two minds on this issue. Off the cuff I agree, but then again where are all the used "enterprise" GPUs coming from right now? There's plenty of secondary market for used Telas K, M and V series GPUs right now and the V100 is only 9ish years old, and that only if you bought it on the release day.

I do agree that 5 years isn't the hard cutoff I was suggesting but I'm not convinced that 10 years is a reasonable timeframe to consider paying the debt down when Moore's Law is involved. I know it's no longer the 12-18mo doubling it used to be but even if it's 2ish years then over 6 years you get 3 doublings or 8x performance gains. At 10 years it's another 2 doublings or 32x performance gains. It's hard for linear payback curves to deal with exponential performance curves past 2-3 doublings.