My new bike is 32lbs, my old bike was 25lbs. 7lbs, wow. Of course the new config is 27.5 not 26, and aluminum not carbon so that right there is most of the difference. Still, 7lbs. I took a look around just for goofs to see what it would take in dollars to reduce the bike by one pound and it’s not cheap - not even a little bit.
Looking at the fork, the only real option for a truly lightweight fork is a RockShox SID but that tops out at 120mm so it’s out of the question. Besides, the lack of adjustability on the SIDs is also an issue. The Pike would shave about 200 grams off but that’s $700ish for around .4 pounds “savings.”
Another obvious place to save some weight is on a new carbon wheelset… That’ll run you around $1600 or more depending on brand. Yikes.
Next up are things like cranks and pedals. Going to SRAM XX1 carbon and Crank Brothers Eggbeaters Ti would take off .75lbs… for just a mere $1k. Um, wow. Surprisingly a higher-spec cassette doesn’t really save all that much weight unless dropping 100 grams is worth the $500 to you.
Ultimately, if you want the lightest bike possible you’re going to have to start out that way to begin with. Swapping parts will only get you so far and will cost you an arm and a leg. It’s just a lot easier to drop one pound off your fat ass than one pound off of the bike.