Well... there are tubeless tires and then there are tubeless-ready tires. True tubeless tires also have an extra layer of rubber inside that stands in for the tube to make them more airtight. So you might be overstating the weight savings. Just hunting around for an example, this tire is 110 grams heavier in its tubeless version. Still, the advantage is real, and obviously greater for plus or fat tires. I also noted, while looking for my example, that the folding, non-tubeless tires are disappearing. This leaves two categories: tubeless folding for enthusiast or race, and tubed wire bead for the cheaper market.

I think it's also getting better as the companies gain experience. The 2016 Schwalbe Pro One Tubeless for example scores higher on this guy's test than the 2014 Pro Tubeless and it's three ounces lighter. It uses all the same technology marketing buzzwords as the MTB tires.

The advantages of lower rolling resistance and lower pressure seem like a bigger deal than the weight.