You're not taking into account the thermal strain on the machine, though. A machine that's 100% utilized (even worse if it's in bursts) will last less than an idle machine.
Out of our >3000 currently active Apple Silicon Macs, failures due to non-physical damage are in the single digits per year. Of those, none have been from production systems with 24/7 uptime and continuous high load, which reflects your parenthetical.
Perhaps we haven't met the other end of the bathtub curve yet, but we also won't be retaining any of these very far beyond their warranty period, much less the end of their support life.
It’s three years for Macs, though I believe you can pay annually for longer. Five has never been a thing to my knowledge.
How much though? Say I have three Mac Minis next to each other, one that is completely idle but on, one that bursts 100% CPU every 10 minutes and one that uses 100% CPU all the time, what's the difference on how long the machines survives? Months, years or decades?