No argument here!
I'm just taking (minor) issue with the assertion that relatively few engineers want to do contract work. If that were the case you'd expect some contractors to wish they were perm. I think the benefits I outlined are such that quite a few do want to. I've also run into quite a number of perm folk over the years who want to do it but don't quite have the confidence in their own skills to make that leap.
I was one of them!