Generally speaking, it's unsportsmanlike conduct to kick a man while he's down. After you've won the battle, it's usually good form to show respect to your opponent, no matter how bitter the rivalry leading up to the conflict was. Having said all of that, the repeated potshots that Netflix has thrown at Blockbuster over the last few years have all been comedy gold.
At first, the shots were subtle. Netflix would greenlight documentaries like The Last Blockbuster as they cheekily winked to the audience at home. Now it seems like the streaming giant is taking it a step further by producing an entire series around working at a Blockbuster.
In the post linked above, you can look at the first images for Randall Park's new series Blockbuster. Depending on what era the series takes place in, there have to be at least a few ironic jokes about Netflix and its eventual takeover.