Generally, yes, often an order of magnitude more expensive. A 4 pound tent you can probably get for a few bucks at a yard sale, but a 1 pound tent is probably $500. Walmart probably has 4-5 pound backpacks for $50, but a 1 pound backpack is going to be like $200-300.

That being said, a lot of it is mentality. Carrying lighter food, not carrying too much water, not bringing extra clothes.

Also, it's totally possible to make your own ultralight gear for a big discount. I got into sewing and have made several decent 1.8 pound 50L packs for only about $80 a pop. Check out https://learnmyog.com/