I believe there is no "one 3d app to rule them all". All have their strengths and weakness.
As to Silo and Amapi and Hexagon, and Zbrush, they are mainly dedicated modellers. So IMHO including a renderer in any of those is more an extra feature than the program's strength.
Sometimes programs overlap . Like silo and hexagon doing displacement painting, opposed to mudbox just doing displacement. And the list goes on.
What I do know is that I'ld suffer if I had to use only one program. Why? Because at least now, there is not a single program that does EVERYTHING fast, efficiently, and is affordable.
Blender is probably the most feature rich 3d program, is free, but if it was so easy to use, nobody would buy Maya or Houdini ;)
I do my tree stuff in Vue, btw
