They've been way behind on adding standard features that their competitors see lots of benefit from. For example, YouTube was years late to the 'channel memberships' game despite the popularity of Twitch and Patreon. YouTube still lacks many of the popular streaming features from Twitch, and only relatively recently got around to adding stuff like polls. I can't think of any feature in the past decade that was a YouTube innovation rather than an innovation from competitors that was copied over years later.