as for the XPORT emus and GPL code, the way I remember it was.... XPORT had been given unreleased code from the authors of the psx emu, which makes the issue kinda iffy.
As for the Xbox Scene, what Large Dopant white said is mostly in line with what I feel. The lack of a legal XDK is unfortunate, but we all know, 'it will never be better then the original', and the MS one is more or less available to anyone who has enough brains to use it.
As for xecuter... they are not just a team that releases software, they sell chips; they have a business to run. Does their bios help them in shelling chips? Perhaps. Is the reason they dont want to share code/findings because they are afraid of loosing that 'edge' in the modchip market? Again, this could be the case, and I dont feel its my place to point fingers.
Of course, xecuter is not the only one at 'fault'. Evox was the big name in bios's and their dash was used 95% of people in the scene for a good year. Evox however, has nothing to lose if they were to share their code. So why dont they? The way I see it, they have pride in their work, and know that if they do release, there is a GOOD chance that someone else will build off their sources and release that work, thus, evox loosing their 'props' in the scene.
now, Complex, there have been some rumblings that they have something in the works, but based on the fact that I havent seen them release any source for any of their other work, I'm not expecting anything different in any future releases. It would be nice to see a new group releasing stuff.