It's just the numbers. Eventually all the hardware will fail. Some of that hardware will require a specific set of conditions to fail. Such a condition may be c

It's just the numbers. Eventually all the hardware will fail. Some of that hardware will require a specific set of conditions to fail. Such a condition may be current inrush from being powercycled. Given the scale of a data centre and powercycling it all at once, then some will fail due to that condition. Further to that thought, there must be hardware in that centre which is failing and being replaced all the time due to other conditions, we just won't hear about it because it's part of normal maintenance.