I thought the same thing last night, just watching the folk standing on the embankment opposite the London Eye at midnight.
Some people (inc families with children) had been there since 4:30, 6 1/2 hours standing in the freezing cold, waiting for Midnight. DS would have been bored and cold, and driven us loopy long before the fireworks started.
As for standing in Trafalgar Square, I imagine surrounded by drunks, being pushed and shoved, no ta. I was happier in our living room watching Harry tell Sally he loved her, TVM.
Mind you, I do yearn for the lovely dinner dances we used to go to in posh frocks and Dinner Jackets, in the days before DS .
I do get a slight nagging feeling that everyone is having more fun than us on NYE.