While I love The Toys That Made Us, one of the major trappings of the show is that they really only have 45-60 minutes to cover the history of some of these brands. Much like the Transformers one and how they really touched only the 90s for a sentence or two, it's tough to cover brands that have been around for 30+ years in that little allocated time, let alone a brand like LEGO that compared to everything else on The Toys That Made Us, is the oldest of them all
It's one of those things that Bionicle if anything should have it's own episode one day, enough meat on the bone with the history of Lego's financial issues in the late 90s and the lore to make something fun and entertaining.