Four pounds for a sleeping bag is incredibly heavy.Good quality sleeping bags weighing half as much are rated reliably to 20 deg. Granted, they are typically not cheap, but they will repay their outlay many times over when used. A wool blanket is tough, versatile, and if you are not carrying it, the weight isn't that significant. They are far less efficient that a mummy style sleeping bag, the best type to have.

You can save a lot of weight in your canteen, as well. A really great canteen is a recycled Gatorade quart bottle - light and tough. Match it up with a stainless steel GSI cup ($6) or similar size titanium (expensive, but tough and lighter). The standard here is a liter size Nalgene water bottle, so common that it has become a standard module for pack pockets, etc. The GSI cup is specifically designed to slip over the bottom of a Nalgene.

You can fabricate any of several alcohol stoves at negligible cost that will outperform an Esbit tab and not deposit gunk on your cup.

While there is expensive lightweight gear, there are also functional, cheap alternatives that work quite well.