So what exactly is driving the developers to keep going?

[Lauront]

Orthodox Christmas is always on January 7th, not the 4th.

I knew some pedant would try this, so it's fitting it'd be you. You do realise there's always a lead up to holidays like Christmas (hence, "holiday season" - it's common for people to book time off around the actual day), and if you're doing savage, most people aren't going to clear it same day, right? So there needn't even have been a holiday around the 4th, but as it just so happens, there is.