Greetings, siguy,
Too bad about the saw, but my impression was that the wire saws are intended for "emergency" use because they can be curled up and take up so little space. Thus they can be easily carried in the pocket as part of a "survival kit." As you found out, a wire saw is not any sort of "superweapon" but it is better than trying to cut a sapling with your teeth

. You might want to read the thread started by Coops asking about small wood burning stoves for camping. At 18th century reenactments much of the cooking is done over coals and small saplings 1 to 2 inches in diameter would be adequate, especially for "emergency" use.
I have had occasion to cut a LOT of saplings while clearing brush here around the yard and also out in the woods where I go deer hunting and I have found that an ordinary bow saw seems to work best. Even so, you will eventually break a blade so get several replacement blades. This is not a big deal as they are not expensive and are easy to change. You will generally get quite a bit of use out of a blade before it gets dull, rusts, or breaks. In fact, I actually broke a bow saw handle ( the steel tubing kind ) once, but only after a great
deal of cutting, so I guess I got my money's worth. These saws are not too expensive, so we always have three or four lying around. Of course, they are much bigger than the tiny wire saws, but if you need to do lots of cutting, a bow saw is best.
I have also used the "hunter's saws" or "Japanese saws" that cut only on the pull stroke. These are generally about the size of a large knife but are much lighter and often are made to fold up and can be carried in a sheath. These are available at hunting supply stores and might be just what you need if you have to carry the saw into the woods. I have had good luck with a couple of these, but, yes, the blades can break! ( Apparently, ANY sawblade can break! ) Also, it takes some getting used to because they only cut on the pull stroke.
You are right about dry vs. live wood and also it seems that different species of wood will tend to cut differently.
Last but not least, let me point out that there is a sort of "knack" to cutting wood. I have found, for example, that even a small sapling about 2 or 3 inches in diameter can cause problems. If it is, say, six feet tall, when you start to cut through it, it will sag onto the sawblade and put a surprising amount of stress on it, possibly leading to breakage. I will generally push on the sapling in such a way as to OPEN the cut to relieve the stress on the blade.
.......Dan