Informative Masahiro Sakurai said he plans to finish his insightful YouTube channel which provides would-be developers and game enthusiasts with a wealth of information on video game making and a direct insight into the mind of Mr. Sakurai. It has not been revealed why he decided to close the channel, but there is no doubt that video game development is tempting him and he most likely does not want to share his time. Luckily, all the videos will still be on his channel so you can catch up if you missed them.
Thanks to Grease 1 for the tip!