If It's Going Down was the last episode of THE BOONDOCKS it was a brillaint send-off.
I saw an interview with McGruder about whether he would continue making THE BOONDOCKS and I think his answer was made explicit in this episode. Huey is the character that represents McGruder the most and when he told Jack " Not to waste his life trying to stop the future" I think McGruder was talking about himself.
The intent of The BOONDOCKS was to educate, critique, and satirize to the point that people became aware of the social/political reality they live in. In the interview, McGruder stated that everything he presented in The BOONDOCKS is out there now and the information is readily available. He made it seem that his inspiration to continue the show was gone.