Netflix technically doesn't serve anything that isn't monetized
YouTube does, and to some degree non-monetizable content skews the numbers
Also, due to the nature of YouTube a large amount of content is repeated but still taking storage
Netflix needs (1) a copy of say Top Gun Maverick (And maybe variations for different resolutions), YouTube needs a bazillion Copies of it with small variations, clips with different music, people "commenting" on it, people actually making commentary, Highlights, YTP's, etc all of it with a wider range of resolutions and also to way more people, plus the overhead of checking against their master copy of copyright infringement
Netflix needs (1) a copy of say Top Gun Maverick (And maybe variations for different resolutions), YouTube needs a bazillion Copies of it with small variations, clips with different music, people "commenting" on it, people actually making commentary, Highlights, YTP's, etc all of it with a wider range of resolutions and also to way more people, plus the overhead of checking against their master copy of copyright infringement