The reason? Laceweight isn't portable**. At least not for me. I do almost all of my knitting while I'm out and about, so projects that I can't take with me just don't get much time. Socks are great, especially ones that I can knit while standing up (read: no chart or one I've memorized). Shawls are good, as long as they are still small enough that I can complete a row in the amount of free time available. I can't stop in the middle of a row - my stitches fall off when I jam the knitting into my bag, and I'm allergic to the rubber used to make the stoppers. (And yes, L, I could just use corks like I told you to, but all the corks in my flat belong to Spouse, Brewer of Booze.)
It's the bag-jamming that's the real issue here. DPN projects go into the WIP tube, then into a zip-top bag. Then the bag gets jammed into my handbag, to do battle with my wallet, my umbrella, an iPod, my keys... Actually, here's a photo of the typical contents of my bag:
If socks get snagged on my keys or caught on the umbrella, it's not the end of the world. They're going to get worn and worn out, a little snag doesn't make them any less wearable. With laceweight, though, a snag would more likely be a snap, ruining hours of work. A velcro snag would be a catastrophe!
I could in theory get proper project bags for my laceweight projects. I say in theory because most project bags close with a zipper, and the few that don't fail to totally enclose the project. I'm thinking something with magnets and an envelope flap, similar to the pocketbooks one sees in posh department stores. But then, I can't imagine a department store selling pocketbooks big enough for a lace shawl, can you?
*I'm lumping cobweb and gossamer in here too, since they all share the same flaw.**Big projects aren't portable either, which is why I've still never knit a sweater***.
***Actually I did knit a sweater, but it predated my discovery of gauge and was knit from rust-coloured acrylic from the 70s that I swiped from my grandmother. I wore it once and threw it in the trash. To the best of my knowledge, there are no photos proving that it ever exists, and that bodes well for the future of my knitterly credibility.