My intuition would be that constant usage (not exceeding maximum rated capacity/thermals/etc.) should generally result in less wear compared to the more frequent thermal cycling that you might expect from intermittent use, but maybe there's something else going on here too. I suppose this would depend on what exactly the cause of the failure is.

Either way, these are obviously being intentionally sold to be used for non-gaming-type workloads, so it wouldn't be a good argument to state that they're just being (ab)used beyond what they were inteded for...unless somehow they really are being pushed beyond design limits, but given the cost of these things I can't imagine anyone doing this willingly with a whole fleet of them.