These holiday months are primed to set records for total hardware sales. Switch has already been setting records all year. Now add in 2 new systems...there is going to be a lot of hardware sold.
Still hard to compete with 07-10 when you also had NDS/PSP on top of three consoles though.
Total top 5 - 23.7M
That is going to be hard to compete with. Between PS4 and PS3, highest Dec ever is PS4 2016 4.9M alongside Pro launch. Between XBO/360 is 360 2011 at 4.0M.
New consoles probably cannot get that high in launch year, but even if they did, and NSW cracks 8.0M, that's still only a total of 16.9M. And realistically there is no way that the twins hit those numbers this year, given supply and pricing.