Yes, that is my concern too, but not as much limited to LW9:
When messiah:render was first announced at Siggraph 2000 (if I remember correctly), there was a big need for better renderers. The big packages internal renderers were not very exciting back then…(I think there was even an option announced to buy messiah:render as a standalone renderer)
But pmG wasn’t the only company who smelled that at the time. Today we have Brazil, Vray, Final Render, Turtle and dozens of other renderers from free to expensive. Many of them are quite mature as of now and well integrated into the big packages.
When I did my first own render tests in early 2002 with the so called “advance” edition of messiah (some kind of open beta) for an article in a german CG-magazine, I came basically to the same conclusion as you have come to in 2006.
One of the results (The BeeMan is a model from Christophe Desse):

Heck, I saw great opportunities for messiah in architecture back then, since it did eat even big scenes in a fraction of the time LW needed… :shrug:
I would never have guessed, that journey would take that long.
Today I don’t see a market for a renderer anymore. Maybe it can survive in it’s niche as a character tool if some quite good, easy-to-dress and fast-to-render hair is added, but other than that?
How long can a tool be “promising”?
Cheers,