Assuming you are prepared to stay within certain tight constraints, it is now possible to legitimately publish your own commercial Traveller products.
On the one hand, that’s fantastic. I must admit, I am sorely tempted to do just that. Self-publishing in downloadable pdf format is easy, and self-publishing using services such as lulu ( http://www.lulu.com/ ) isn’t much harder. I’m not naive enough to think that this would be profitable. But it would allow me to contribute an official Traveller product.
On the other hand, other people (not many, but some) are already doing it. And that means that the completist Traveller collector in me feels the need to buy them.