So small arms development did stop at the AR-15? Wow, I didn't read the memo.
Back to replacing a weapon with another model of similar capability: I'll parallel this with the replacement of one car with another. I used this argument about twenty threads ago, but I'll recycle it. It's like replacing a 1995 Toyota Corolla with a 2003 Nissan Altima. Sure, there isn't really that much wrong with your Corolla and it still gets about the same gas mileage, has airbags, CD player, etc. In fact, they are virtually identical in most respects. Why would you not buy another 1995 Corolla?
I frankly don't get what the point of quoting me saying that "The XM8 was a fallback plan if the OICW didn't pass the mustard" is. Is the implication that I was somehow suggesting the XM8 was inferior and they considered the OICW better? If so, you are incorrect. My statement was meant to reflect that H&K was practicing good business by developing more than just a monster weapon and thus they have a resiliant design to back it up.
To illustrate, the G36 sprouted from the background as the G11 failed miserably. By further developing and tuing the G36 for the possible American Market, H&K was positioning themselves for a move on that market if and when it materialized.
The British and US sure as heck failed to practice this. They put all of their eggs in one basket on more than one occassion. Look at the development of the M-14. It was intended to [snicker] replace the battle rifle, submachinegun, machinegun, and even pistol in some cases. They asked too much of one weapon system and doomed it to failure from the start.