But in the end i will say you are right, i play long time with a average stamina below 4 with my team, and didn't see crashes in the 2cd or 4th quarter more then my opponents, and i know that some of them train it from time to time. And even my stamina 1 guys, sometimes make good final minutes.
fact - stamina is more important when you play haste tactics (look, push, run) than slow tactics.