Remote Remote Control

Lately I've been running into remote control issues. That is, GUI desktop and server remote control technologies, particularly as espoused by VNC as well as others. A couple of questions occur:

1. Why are there so many VNC implementations? The code is GPL, I understand, but do we really need RealVNC, TightVNC, TridiaVNC, Ultr@VNC, etc.? I could understand perhaps the oddly named and separately maintained VNC client for some obscure platform, but most of these seem to be pretty much alike in terms of deployment, and differ on supported encodings and compression schemes/wire protocols. I guess I'm just hoping for more eventual cooperation and consolidation.
   

   
   

2. Why does RDP exist? I realize the answer is mostly "because Microsoft wanted it to", but it continues to stick around in Windows XP (and presumably will later as well) even though VNC is around. I guess the GPL is one reason. Besides, it's not like Microsoft has a history of just jumping on board with whatever open de facto standards are around, but it would be nice if RDP was more openly documented outside of what has been teased out of Microsoft's implementation and put together in rdesktop. It would also be cool if RDP could be just put into a multifunction VNC implementation.
   

   
   

3. Sun's Sun Ray? Yet another proprietary gizmo? Why? Again, at least some people are hacking it.
   

I did find an OS X native VNC server that looks okay, though I've not yet put it through it's paces, and have also managed to stick with an okay VNC client that doesn't crash, although it does lack some features and posses some bugs.