I think MS with their aggressive holiday approach every year has trained consumers to buy like that. Ultimately it's less profitable then selling the same number at a higher average price throughout the year. I think that's why Sony has taken a different pricing approach.
Microsoft makes it's money mostly with the Gamepass and software sales. That said, a permanent pricecut for both of them is way overdue
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454