those were the days... I purchased my OG Xbox in early 2005 and I miss the E3 now that we have a very toned down Summer Game Fest 2024, and also miss the happiness of those days, like in this 2 minute video....Xbox had a 128-bit memory bus, so increasing memory wouldn't have changed bandwidth.
IIRC, Xbox used DDR200, while DDR266 and DDR333 were available (but more expensive), so more bandwidth was possible but obviously not deemed worth the cost.