Third Part Renderer's

Why are third party renderer's eg. final render,vray etc better than max's 
scanline renderer.  Why can't discreet produce equivalent or better 
renderer's than those mentioned above.  Why do we have to spend thousands more
on 
top of what we already spent in buying your product to get superior 
results.

Its just my opinion (and currently I'm only using Scanline and Mental Ray) 
but I'd prefer large 3D programs like Max / Maya focus thier efforts on the 
vector side of things, which is what they are best at and where the 
innovations are coming from.  Afterall, how good a renderer is depends on the 
pipeline and type of work, and not necessarily a blank notion of
"quality."  
Which is it, speed, scalability, compatability, realism, effects, on and on.

It seems like most of the compatibility problems I've seen result from 
inconsistent use of raster methods like procedural maps / particle rendering / 
dealing with light techniques etc.  These things shouldn't be glued to the 
creation and animation program, and the user should be able to choose the 
best app for creation and animation ... and then the best rendering 
solution.

I'd prefer a 3D program do an excellent job of telling a renderer where the 
lights are, where and how to use maps, where the particles go etc and any 
renderer should be able to plug into the pipeline seamlessly and do it's 
thing; 

So I guess where I'm going with this is that Autodesk should spend thier 
rendering R&D making things more compatible and not on improving a "max
only" 
defacto rendering solution like scanline ... it will never be as good for 
any given thing as a competitive free-market 3rd party renderer.