Bruh I dont even know where to begin to explain why this is the most simple “I dont actually understand how anything works at all” take of all time. But I will try and break it down for you:
They have a tonne of redundancy, do you really think there is just one single computer running something like WoW with no redunancy at all? Really?
There was an article in 2009 discussing wows server requirements at the time and it was 20,000 systems to run their whole platform at the time, WoW alone was using over 13,000 blades running around 75,000 cores and over 100tb of RAM spread across 20 data centres around the globe.
Redundancy the way you are talking would require them to purchase a second set of all of that, double the amount of work required for any upgrade or patch, significanly increase the complexity and expense of each maintenance as you cant just shunt that many people around the globe in sync across that many data centres from one set of hardware to another easily. Hotfixes would be slower and far more complicated to roll out quickly and you are basically now doubling the workload of any and all changes that occur and then some.
And THEN after all this insane extra expense of literally double the hardware and maintenance expenditure + the extra from increased complexity and maintenance requirements from the live redundant setup they would then have that stuff just sit around and do literally nothing each week until maintenance time just so they can avoid interrupting people for 1 hour here and there?
This is like buying a bunch of cars and leaving them parked at a bunch of petrol stations across the city and then paying someone to go to those cars and do all the maintenance and keep them fuelled as well as ensure they have a duplicate of everything you carry with you each moment of each day all ready to go so when you stop to fill up you dont have to take the 5 minutes and can just get in the next car and drive off.
Its an insane suggestion by someone who doesnt have the beginning of a clue of what they are actually suggesting.