Sounds like you have shitty friends

Things come up, it happens

Wait until some of you are shift workers, work from home, home owners, long term gf/fiance, married, kids

Shit gets harder as you go on

I will say, if you can't this time then why not try plan a day with everyone yourself? I know you've said you try to always go but why not try arrange something and see how it turns out?

You're going to be apart for a good few weeks and honestly you're most likely all going to miss eachother and I'm sure the group chat will be going wild

I'd try to arrange something for January personally, just let them know that you just can't make it, can we do xyz in Jan when we're all back together instead, first rounds on me or something