They take a long time to make because Var has to come up with an idea to theme each video around, formulate his thoughts on the subject, and write out a script for it instead of the loose style of most TTV videos. Then he has to edit the script, record it, and edit the video (which takes longer than editing almost other videos because it isn’t about a specific news topic or LEGO set).
If a lot of time was put into cleanly editing an episode I’m sure it would do well considering the popularity of video essays and all of the Bionicle nostalgia videos people have been making recently, but Var would need a good discussion topic and motivation to complete the video.