You are probably right. My spinner weighs 6.5 pounds and if I limit it to 20 lbs total, that means my stuff weighs 13.5 pounds. That's where I am more comfortable, even with a rolling bag. Interestingly, I was able to meet that 20 lb goal more easily when packing for colder temperatures than for variable ones. Obviously, if I go up to 22 pounds total, 15.5 pounds of the weight is my stuff.
Your RS rolling backpack weighs 5.5 pounds, so if your total is 13-17 pounds, that means your stuff weighs 7.5-11.5 pounds. You are really packing light. Your LL Bean bag weighs just over 2 lbs, so that means your stuff weighs about 11-15 pounds if the total is 13-17. In that case your stuff weighs about the same as mine.
As previously mentioned, we usually travel for a month and pack for a week. We use apartment washers, laundromats or have our laundry done once a week. I despise washing things out in the sink and will not do it except in a dire emergency. It's worth the extra weight to not have to do that.
I don't know how old the OP is or how big she and her husband are, but I will turn 69 this month and my husband is 66. We are both XL-XXL size people. I can assure you someone's size 8 pants weigh less than my size 18's and take up less room. And if I take a 2nd pair of my size 10 shoes, they will weigh more and take up more room than someone else's size 7's. My 6'4" female cousin would have an even harder time packing very light.
Beyond all that, I have knees that are going to need surgery before too long. I get shots before each trip and it helps, but my doctor has told me to take one step at a time when going up or down stairs and avoid them completely if possible. The last thing she wants me to do is carry extra weight on my knees or my back.
Bottom line, it is highly unlikely that I will ever go back to wearing a backpack. When I can slip the handle of my spinner through the double zipper pocket on my tote and not have any extra weight on my body when wheeling everything around in airports and train stations, I'm definitely going to do that.