I am one of those newer subscribers, with really only starting with SYSTM and Sufferfest a couple of years ago. The humour is what drew me; as I said in an earlier post–if I just want to workout with intervals, I can do that far cheaper by using pure Zwift and/or my own interval sessions…the storylines and jokes are incredibly motivating to get you to go harder than you would think you can otherwise.
(Then discovering the support group and culture around Sufferfest, which was even better to help with motivation.)