The standard advice for a heavy pack is to attack the big three — your backpack, your shelter, and your sleep system — because they are the biggest single items. This is correct, and it is the first thing anyone should do. It is also where a lot of people get stuck for years, paying steeply diminishing prices to shave grams off items that are already light, while the actual weight problem hides in plain sight.
Where the trap springs
Once your big three are reasonably light, the next pound is not in them — it is scattered across the dozen small things you never weigh. The oversized first-aid kit, the spare clothes you never wear, the gadgets, the "just in case" pile. Each item feels too small to bother with, so none of them get cut, and collectively they outweigh the few hundred grams you are chasing with a more expensive tent.
The diminishing-returns wall
There is a point where a lighter big-three item costs a lot of money for a small weight saving and a real loss in durability or comfort. Past that wall, you are buying bragging rights, not a better trip. Knowing where your own wall is — the weight at which further savings stop being worth it to you — is more useful than any gear list, because it tells you when to stop shopping and go walking.
What to do instead
Do the big-three cut once, properly. Then weigh everything else, lay it all out, and remove rather than replace. The lightest item is the one you left at home, and it is free. Chase the scattered pounds before you chase the expensive grams, and you will end up lighter, richer, and a lot less smug.