I was in a outdoor store the other day and saw they were selling individually packaged skeletonized titanium tent stakes for $4.99 each. Actually savings over my normal aluminum ones would have been on the order of 0.3 oz per unit. A little math on my handy calculator showed me I would be spending around $266/lb. I elected to pass.
A couple of years ago, I worked out that most of my gear could be upgraded to a equivalent spec, but lighter version at an average cost of $10/oz. I guess you could say that was above my comfort threshold. After considering that scary number, I made the decision to upgrade primarily as I wore stuff out. I'm sure now the cost would higher now, as I have replaced some items over time with the lighter versions "as needed".
I've also looked for other, cheaper, ways of dropping weight. Modifying existing gear or just leaving more stuff at home has been my most effective moves of late.
I could probably afford to upgrade more items, but have learned over time that it's far more effective to put the money towards actual hunting expenses. My sheep trip this year cost nearly enough to pay for a Kimber Montana..... but I suspect that sitting at home with a sweet new rifle in the safe wouldn't have been nearly as fun.
Yk