Weight vs Cost Tradeoff

I struggled to achieve the 25 lb limit that had been set for the carrying weight (without water or commissary) for the Somewhere Over the Rainbow (SOTR) hike this spring. This was in spite of the fact that I did not carry any First Aid supplies, cookware and had really pared down on the snacks.
Where is the problem? I have narrowed down the issue to the fact that when I started acquiring backpacking equipment, weight was not a concern. This is the price you pay for doing it the hard way- not asking, not being part of a group and not being perceptive to what the experts say in the magazines / publications.
So, I bought a big backpack and a 15ºF synthetic fill sleeping bag, a 'good' normal pad and never asked about the weight - this was my original equipment for my first big trip- Machu Picchu. Did I carry heavy stuff during that trip! My jacket(s!), fleece, etc wheighted a ton, plus I did not ration what I took. I wish I had weighted my pack during that trip.
My next big acquisition was my tent - I did consider weight- but I still went with a 2 person tent. It was on sale and the excitement of my first solo trip overrode any other considerations.
The first learning on weigh/ cube actually came in the Grand Canyon Rim to Rim- a guided trip where we were told, in no uncertain terms, that we haf]d to fit our personal stuff in a 8 lt bag - I forgot to fit my toothpaste!! Amazingly, I survived the trip- except for the toothpaste never missed anything.
For the the most recent trip (SOTR), our guides defined a limit of 25 lbs, which I was never able to achieve. I dropped all my snacks and used everything I took. Still, I was at 28 lbs. My backpack (a REI Galaxy) and my Big Agnes encampment sleeping bag account for, what I believe, is 3 to 4 additional lbs of weight that I could shave off.
Then I look at functionality, weight and cost. In both cases (sleeping bag and backpack), the functionality is there. I actually LOVE my 15°F Big Agnes Encampment sleeping bag. It has gone with me to ALL of my backpack trips (except Ciudad Perdida- took a 50° REI sleeping bag- did not really need anything warmer in the jungle) and I sleep like a baby when I am inside it. The system by which the pad is slid into the base of the bag works well for me (specially with the new, ultra lightweight pad that I got for SOTR), so I am a truly 'happy camper' regarding my sleeping bag. Weight and cube is the issue. There is an equivalent Big Agnes, down filled sleeping bag that weighs 22 oz less and compressess significantly more - at a cost of ~$420. Is this worth it? I will be doing 2 additional 'big' hikes this year (Adirondacks in July and Yosemite in August) and, I am sure, more will be coming next year.
The SOTR trip was a milestone in duration and trips of 7+ days will become more common than before. Weigt considerations become more critical as length of trip extends as carrying food increases the weight significantly.

Now, a year later, I am down to 31 lbs for a weekend trip - including water and food for 2 days. I am getting there. Have acquired a down sleeping bag and a much lighter weight backpack. I am learning to calibrate my water needs and I believe that I can still reduce my weight on the clothes side and the snacks.
This September I will do a 10 day hike - the Wonderland Trail- and I will have oto keep on working on weight reduction.