Me thinks you assume too much infantry combat in open terrain, in tank or mountainous terrain.

Combat in settlements or forests leads to completely different conclusions - and these are two of the three terrain types that infantry is really needed for (urban / forest / mountain).

This expeditionary nonsense of fighting against poorly trained, equipped, supplied and supported paramilitary forces at the end of the world leads to completely wrong conclusions.

It's like the "The Boers shot at us at 800 m and did hit us (rarely)!" outcry of the early 1900's that was extremely misleading in regard to the REALLY important warfare that took place during 1912-1921 in Europe.