It depends what your local average trail is.
I am not arguing against light bikes, not at all.
I cannot stand bikes that wrench my sockets when I try to lift them.
My belief is that most bikes will be sub 20lbs ten years from now.
My point about 17-25lbs bikes is about luggability.
Once you get up to 30 lbs range bikes get unweildy to flick around without downhill momentum. We are talking leverage.
You can still lever a 25 lbs bike around fairly easily.
We generally reach a point where it gets too heavy, unless we are Arnies.
My point was that bikes are still luggable and chuckable until they get up to the 25/30 range, so something 17lbs won't be that radically better.
However, like motorbikes, you can throw anything around when you have the grunt.
Sorry if I sounded anti weight weenie, which would be ironic as I am a reformed weenie myself. I did not mean to come over that way.
Lighter is always better for fuel consumption, but just like a lot of nice cars I have had they may handle better with a little ballast.
The doctor diagnosed me with hereditary diarrhoea. I can't understand, I wear a kilt.