While the video brings up a worthwhile topic, it may also risk simplifying things to the point of patness, and concealing the true hardships of game design.
For example, over the years the Civ games have increasingly catered first to the preferences of hardcore strategy gamers, then to the trend of feature bloat in AAA games. This process has made them diverge further and further from Sid Meier's own clean and breezy game design style. Sid is not just passing his mantle to other designers; these hugely complicated games simply cannot be produced by his own design philosophy.
All of these are obscured by the marketing value of the "Sid Meier's" brand, which created among the vast majority of players false expectations about what a Sid Meier game means, and felt cheated and betrayed when games bearing the Sid name do not meet these expectations.
Meanwhile, Sid himself kept experimenting: in the recent decade he designed or led the design on the console game Civilization Revolution (CivRev), the Facebook social game Civ World, the Ace Patrol series, and Sid Meier's Starships. Some of these experiments are more successful than others, but many an uninformed hardcore gamer is unable to criticize them on their own terms, and lumps them all together as "shoddy cash-ins." CivRev was meant to be a back-to-the-roots version of Civ influenced by more recent game design trends. Civ World was an attempt to reach a larger audience, and motivate them to participate in large-scale cooperation. In a way, Sid hasn't stopped making Civ, he's simply trying out new ideas that are quite different from the direction the numbered Civ series is set on.
Thank you for this video.
By the way, I have also noticed that some design decisions of Civ6 came from the "Sid Meier's Civilization: The Board Game".
Not sure which specific ideas you are thinking of, but they may also originate from CivRev, which the board game is heavily based on.