IMHO Blitz has been dead for sometime and is just fading away ATM while TGC have propsered by understanding what their community wanted and giving it to them.
BS!! I will agree that Blitz is in a transitional period. You have Blitz3D which yet dated, still delivers. And then you have Max which is very promising but a bit too complex and has no 3d module yet.
Either updating Blitz3D to DX9 or releasing Max3D will fix the problem.
But there's no fixing TGC. They suck the cash outta you like a Hoover and give you a language that can't do anything at a decent framerate.