Do this 3 or 4 times and he made less gold and is a level behind.
Aren't we forgetting the self-correcting nature of xp gain in 3.5? If you are lower lv than the rest of the party, you get more xp from any given encounter. Which means that it is actually advantageous for the wizard or party crafter (eg: warlock or artificer) to consistently stay 1 lv behind the rest of the other PCs, as this will net him more xp (which can in turn be used to craft even more gear), and this results in a sort of vicious cycle.
If you have time, head over to the CO boards on the gleemax forums and search for a thread called "Riding the gravy train". It has the math to back this up.
