LOL.. You're totally correct. A few months of being down 120k isn't going to mean a whole lot when Switch dominates Christmas by a large margin. Sony has put out more major first party software in the spring and summer whereas Nintendo focuses that content more around Christmas when people are buying consoles in droves.
Here's my two cents on it. PS4 has plenty to push sales this Christmas, possibly including another Black Friday deal. The real concern for its sales is that the console is finally approaching market saturation, whereas the Switch has a much larger base of customers that may want one but don't own it. A lot of its heavy-hitters this season are also available on PC and Xbox, which will fragment things somewhat (though those games are still most likely to sell best on PS4).
This year, the PS4 is down a bit over last year. Next year, the PS4 will likely be down over this year. It'll still sell great but slowly decline until the PS5 is announced. Switch is (so far) on an upward tick because it's newer and just as popular as the PS4 was in the same time-frame.