I'm actually not too surprised by that game Monkee. 25 usage and 19 are not huge differences. If you had real big time scorers like Jordan, kobe, mchale, etc. as opposed to magic and marques johnson, then it would be surprising.
Plus, Marshall played 41 minutes while only 1 of the 3 25usage guys played more, so he was the primary or secondary option for a large amount of minutes.