Has there ever been a war where small arms turned the tide?
Disease and weather killed more than battle through the civil war period.
By WWI heavy machine guns and artillery were causing battlefield casualties. I am not sure if the disease still killed more in WWI or not, but it was at least close.
Russian tanks and US & British firebombing destroyed germany in WWII. The number of tanks on the Eastern front was incredible. Glantz and Frieser say more tanks lost at Kursk than ever present on the western front.
Now even infantry tactics often rely on calling in firepower rather than winning with rifles. There are obviously exceptions in circumstances where support is not available or viable.