Yes, just imagine how much weight could be saved by replacing all those nuts and bolts with Titanium ;o)
10.5 kg is very light to start with. But saddle, wheels, pedals alone are potentially 2 lbs to save without trying too hard. And you can always remove the mudguards
There is a point when it doesn't really matter too much. You can carry a folded Bickerton around with two fingers.