It's more about what you have achieved in your career, but it may indeed have been viewed as a better strategy to wait until after you get admitted to quit your job. What if you don't get in? The b-schools may consider the judgment off there especially if they compare you to others with a similar background who may have pulled off an impressive application and also carried a fulltime job at the same time. Think about the recent presidential debate. Romney was criticized for "over-preparing" while the president was "busy running the country" and preparing at the same time. Romney clearly won the debate, but not without pundits making this comparison. This is not a political commentary, but rather evidence that you may have higher expectations from the adcoms having had all that free time to prepare your GMAT and application results compared with someone who is still out there working 70 hours a week and also submitting a competitive application.
Loud and clear! Many thanks