This! Also, you'll see a LOT less warranties on Frames.How light a bike is really depends on the build more than the frame. The super light XC frames are 4.0 to 4.8lbs with shock the rest of the weight comes from the part spec.
Right now a top of line build on a light FS frame (like an Oiz or Spark) is around the 22lb mark. Going significantly lighter is possible but durability and performance compromises are being made.
Interestingly XC FS have been about 22-23lbs for the last 10 years. What has changed is the newer bikes are way more capable.