Product life cycle exists insofar as parts become increasingly difficult to acquire. That being said, Leica still makes the M-E, which has the guts of an M9. There are no signs M9s will be "in trouble" for the foreseeable future.
I think the unpopularity of the M-E has a lot to do with the relative "glut" of M9s on the market. The M-240 release saw a lot of people selling cheap M9s - cheaper than a new M-E. Many photographers enthusiastically buy used equipment (myself included). Anyone who wants to buy a new CCD Color M will buy a M-E, they will eventually hit the used market, and budget-conscious buyers will have reason to look at both.
I sold my M9 because it was impractical in situations under EV of 4. In situations above EV 4 it had amazing IQ and awful handling. The handling was not bad enough that I ever picked another camera over it, however. I have a certain fondness of the images I shot with it, though I can't say that that the fondness was caused by any technical merits.
I am eagerly watching the used prices of the M-240 drop.