John Lennon - Happy Xmas (War is Over) Lyrics Meaning

(So this is Christmas and what have you done?)
What have we really accomplished with this biggest event of the year? Money, work, effort, what have we really done?

(And a happy new year, I hope it's a good one with out any tears)
I take this as sarcasm. Producing tears is as much a tradition as Christmas. Of course the new year will be the same because no one will change anything. He adds that peace is possible.