I would say it's a little of both, Philly. I, for example, only do DX themes and widgets for WBs that I like, unless it is requested of me. There are a few skins by Stardock Design that I would love to do, but they never respond to my requests. So I just quit asking. A big NO is better than no response at all, which is what I get from Stardock Design.

Most skinners will grant permission if you do good work, and someone else hasn't beat you to it...lol. I have blanket permission from a few skinners here. Good guys to work with. I see that as my work has improved, I get more yesses(?).

I like the program that Deviant Art just started.  They started a program whereby artists can sign up to have their work be opened up to other skinners for additional skins/accessories as long as credit is given to the original artist -- sort of a blanket permission statement, so when the muse hits an artist, they don't have to put their project on hold, searching down an artist and getting permission.

To that end, I want to state that anybody here has my permission to use my work to base their project off of as long as they give credit to me.  I doubt that's going to happen anytime soon, though, since you said "there are some very outstanding Themes in the WC Gallery" and none of mine are outstanding....yet.

I still try to update my old skins....slowly but surely    as for extra stuff, i make most of my own, but i will give out permission after I have checked what was made and think its to a standard that i would accept.

As quickly as WB changes, especially thesedays, its almost a full time job to keep up with legacy support, we try tho.

Btw , your doing a fine job on this. 

Thanks for the replies folks.

 (Hope this little bump doesn't bother folks, would like to see some more replies.)