What's most likely up is that artists aren't paid nor obligated to do these requests, which means most of them take an exceptionally long amount of time to get done, if ever. The bulk of activity on an episode's page is usually 1-2 days after the episode airs. We have a feature on the site to let vector artists find unfinished requests, but with their number being in the 100s at least and not many people actively doing them I would not hold my breath.