While I agree your explanation is valid and probably swayed enough politicians of the day to support standardizing the 03, there were other reasons.
The parts interchangeability problem was never fully resolved. From what I've learned, 90% compatability by the end of the war was the best they could do. Perhaps they could have achieved 100% if the war had gone on for a few years.
According to C.S. Ferris:
The government had financial issues after the war. Springfield Arsenal would have had to retool the factory and train their workforce to build the 17s. There was no immediate war to fight. It was much cheaper to just keep on building the 03s.
The government didn't want to run the risk of losing control of rifle manufacturing to strikes and bankruptcy if it allowed private companies such as E, R and W to continue to build the 17. Both occurred in the years following the war.
The 17 was a superior rifle in some respects. The strength of the 17's action was obvious. However, according to Ferris, the 03's rear sight configuration was identified during the war as a design deficiency that needed to be corrected. The 03-A3s that were built later had (guess what?) a re-designed rear sight that somewhat resembled the 17's rear sight. It was moved to the rear side of the action like the 17 and had protecting sides that were similar to the 17 although a bit smaller, and kept its windage adjustment.
I have an 03-A3 and the rear sight is fine however, the front sight takes some getting used to. The thin blade makes target acquisition difficult at times. Target acquisition has never been a problem when I shoot the 17.