As you level, you will buy new ranks of spells. If you splurge out on an item upgrade, you will not have enough gold readily available to upgrade to the latest ranks of spells: placing you behind. Moreover, you can buy gear upgrades from the Auction House (AH) or vendors. Furthermore, you may have large investments that need to be paid for professors. You will need to purchase reagents and items such as leather, bolts of cloth, alchemy supplies – unless you have a charitable friend or another high-level alt.
HOWEVER, I did find out that there was an exploit to get around it (one of those rare exploits where you would WANT a bit of lag). Basically if you spammed “X” to sit/stand/sit/stand, then if a mob hit you while you were sitting and right as you were standing up, then it would register as a crit, but on the server side you would be standing, thus allowing the ability to proc.
This was a good start, but there were issues with how the developers used to handle updates to the database data. Unlike the source code, for which Blizzard had archives for multiple branches of the game that could be worked on and developed as separate pieces, early database data was overwritten with each commensurate update. Thankfully, that problem was fixed very quickly after launch, and when we looked, we found data going back to version 1.12—and even earlier.